< RAZPRAVE GEOLOGI A POROČILA GEOLOGIJA RAZPRAVE IN POROČILA 9. KNJIGA LJUBLJANA 1966 VSEBINA — CONTENTS Ra^oičič, R. Microfacies du Jurassique des Dinarides externes de la Yougoslavie . 5 Sribor, L. Jurski sedimenti med Zagradcem in Randolom v dolini Krke ... 379 Jurassic Sediments Between the Villages Zagradec and Randol in Krka Valley.....................382 Buser, S. Starost plasti z algo Sphaerocodium bornemanni Rothpletz v slovenskih zunanjih Dinaridih.................385 The Age of the Strata with the Alga Sphaerocodium bornemanni Rothpletz in the Slovene External Dinarids.........388 Hinterlechner-Ravnik, A. Ignimbritni tufi pri Podljubelju...............391 Ignimbrite Tuffs at Podljubelj (Slovenia)...........398 Jelene, D. Adola Gold Placers and Nickel-Chromium Ore Deposits.....403 Hamrla, M. The Iron and Manganese Ore Deposits in Ethiopia........439 Nahajališča železove in manganove rude v Etiopiji........486 Zlebnik., L. Hidrogeološke razmere na območju strojnice elektrarne Srednja Drava 1. stopnja......................489 Geologic and Hydrogeologic Conditions in the Powerhouse Site of the Srednja Drava I Power Plant..............501 Fabjančič, M. O baritu na Slovenskem.................. About Barite Occurrences in Slovenia.............524 Turnšek, D. in Buser, S. Razvoj spodnjekrednih skladov ter meja med juro in kredo v zahodnem delu Trnovskega gozda.............527 The Development of the Lower Cretaceous Beds and the Boundary Between Jurassic and Cretaceous Formations in the Western Part of Trnovski Gozd...................543 Faninger, E. Hiperstenov andezit pri Sv. Roku ob Sotli............549 Hypers thenandesit bei Sv. Rok ob Sotli............551 P leni čar, M. Poročilo o delu Slovenskega geološkega društva v letih 1963 do 1965 . 555 Ramovš, A. Rihardu Simnovcu v spomin.................557 GEOLOGIJA RAZPRAVE IN POROČILA GEOLOGICAL TRANSACTIONS Ljubljana • Letnik 1966 • 9. knjiga • Volume 9. AND REPORTS----- MICROFACIES DU JURASSIQUE DES DINARIDES EXTERNES DE LA YOUGOSLAVTE Rajka Radoičič Introduction La stratigraphie du Jurassiquei des Dinarides externes se basait jusqu'aux joiurs plus recents sur les dčcouvertes des macrofossiles. Sur les cartes geologiques on a distingue soit le Jurassique non differencie, soit certaines parties du Jurassique aboildantes en macrofossiles: prin-cipalement le Liassiqu© (couches a hithiotis et calcaires varies a Brachio-podes) et le Malm (calcaires a Cladocoropsis et calcaires dits tithon-valanginiens h. EUipsactinia, Poiypiers, Diceras et Nerinea). La fauna de Cephalopodes n'etait connue que d'un petit nombre de localites: quelques affleurements des couches liassiques a Cephalopodes au Montenegro du Nord et a I'Herzegovine et couches de Lemeš jurassiques superieures de la Dalmatie moyenne. Les travaux pour la carte geologique des Dinarides externes au 1:25 000e que Ton execute dans ces demders temps avaient demontre qu'il faudrait disposer des donnees stratigraphiques detaillees et beaucoup plus nombreuses obtenues uniquement par les etudes biostra-tigiaphiques complexes. Les premiers essais des etudes micropaleontologiques avaient dej a offert de tres importants resultats en decouvrant les nombreux microfossiles me me dans les sediments qui etaient terms steriles. II n'etait pas rare que ces sediments jurassiques fussent range jusqu'a ce moment dans le Triassique ou dans le Cretace superieur. Les Etudes micropaleontologiques et surtout les etudes des microfacies avaient sans dcute grandement eclairci les problemes du Jurassique des Dinarides externes — les resultats des travaux executes jusqu'a present dans ce domaine sont l'objet de cet apergu. Etant donne que lee. microfacies jurassiques, prepares pour etre imprimes en 1961, n'etaient pas publics a temps utile, on a fait un complement le plus necessaire en tenant grand compte de la bibliographie apparue sur ces entre-temps. En plus, la presentation de certaines series est complete de quelques donnees plus interessantes obtenues apres 1961. II est a souligner qu'aujourd'hui on dispose de tres interessants materiaux micropaleontologiques d'un grand nombre de colonnes jurassiques de- taillement levies, non seulement a l'lnstitut de recherches geologiques et geophysiques a Belgrade, mals aussi aux autres centres geologiques a Ljubljana. Zagreb, Sarajevo et Titograd. Cela veut dire, qu'aujourd'hui au moment de la publication des microfacies jurassiques, la serie ju-rassique des Dinarides externes de Yougoslavie est etudiee beaucoup plus largement et plus minutieusement que ce que l'on pourrait conclure de ce travail. Au cours de 1'etude des microfacies jurassiques des Dinanides externes ma collegue Aleksandra Danilova, qui travaille egalement sur l'etude des microfacies jurassiques et cretaces d'une partie des Dinarides internes est des montagnes carpatho-balkaniques, n'a pas hesite k m'apporter son c^ncours dans une collaboration utile. Je voudrais a cette occasion la remercier chaleureusement pour cette collaboration de lom-gues annees. Je remercie Egalement M. le Professeur Zarija Bešič et ma collogue Smiljka Pantič avec lesquels je travaillais plusieurs annees sur les terrains montenegrins, ainsi que le collegue Djordje C e k i č pour les photos reussies des lames minces micrc/paleontologiques. Belgrade, novembre 1964. NOTE STRATIGRAPHIQUE Les microfacies jurassiques des Dinarides externes sont exposes suivant les regions respectivement suivant les colonnes stratigraphiques particulieres (fig. 1). La majeure partie de colonnes stratigraphiques tirent leur origine des Dinarides montenegrines. Pour ce domaine on presente, dans le but de completer l'image sur les conditions paleog£ographiques, a cdte des series jurassiques des zones variees des Dinarides externes egalement les microfacies d'une partie des Dinarides internes (zone exteoie des Dinarides internes: le Jurassique des environs de Pljevlje). Sur le developpement de la majorite des series en question on avait deja ecrit (H. Kadoičič, 1963/64); c'est pourquoi on ne presente que les apergus stratigraphiques tabellaires avec remarque qu'ils sont plus ou moins schematises en fanction du degre de leur connaissance. n ne serait pas superflu de repeter la conclusion relative aux caracteres de la sčrie jurassique des Dinarides externes, a savoir: «— la variabilite prononcče de l'epaisseur (de quelques dizaines a plus de 1 200 m); — la sedimentation de l'eau peu profonde, de l'infraneritique k celle de l'eau peu profonde littorale finale y inclus le regime laguno-lacustre dans le Kimmeridgien et le Portlandien intimement lie avec les bauxites et dans certaines regions egalement grandes lacunes dans la colonne stratigraphique, et — la variete des facies du caractere zone, quoique dans certaines zones se sentit une differenciation plus importante dans la direction longitudinale. Temporal re ment, les differentiations faciales s'observent pro parte au Liassique, et surtout dans le Dogger et le Malm inferieur, tandis que rhomogeneite des facies d'une vaste etendue des Dinarides externes de Yougoslavie caracterise la periode apres le Kimmeridgien (s&rie a Clypeina jurassica, serie a Tintinnines aberrantes* eftc----)». L'importance des microfaoies en question n'est pas toujours la meme — je considere qu'il est nčcessaire, pour connaitre le d&veloppe-ment d'une serie, de connaitre nem seulement les microfacies caracteristiques mais aussi ceux de 1'importance stratigraphique secondare ou meme ceux stratigraphiquement indifferents (en ,titre d'exemples, calcaires varies a Ostracodes, Thaumatoporelles, certaines Codiacees, Cyanophytes, etc ) mais qui dans une region restreinte ou dans une zomet paleo-geographique determine peuvent etre les «marquers» stratigraphiques tres importants (par ex., calcaires microoolithiques, certains calcaires oolithiques-d etritiques et oolithiques a Echinodermes, calcaires organa genes-d£tritiques £ Echinodermes, Crdstellaria et autres Lagemdes du Jurassique inferieur c'est-a-dire du Uassique et du Liassique-Dogger). Les microfacies qui suivent sont tres repandus et tres caracteristiques pour certaines periode« du Jurassique des Dinarides externa: LIASSIQUE Les microfacies a __ Trtassina hantkeni, Aulotortus, Sestrosphaera _ Palaeodasycladiis mediterraneus — Orbitopsella praecursor — Lituosepta recoarensis — Spirillina liassica. Trocholina sp. nov. et Lagenides _ Vidalina martana, Glomosyira sp., etc---- DOGGER Les microfacies a __Globigerina helveto-jurassica — Dictyoconus cayeuxi — Selliporella donzellii, Teutloporella gallaeformis — Nerinella _ Trochamminidae, Textulariidae, Verneuilinidae (frequentes) et Endothyra sp. DOGGER SUPČRIEUR ET MALM INFfiRIEUR Les microfacies a — Protopencroplis striata et Trocholina — Pfenederinidae tiru esp< Les microfacies a — microfossiles problematiquies Pr3 et Pr 6, Bryozoaires (?) Br 1, Codiacea C 1, etc. — Labyrinthina mirabilis — Cladocoropsis mirabilis et Kurnubies — Kumubia palastiniensis et Kumubia wellingsi — Conicospirillina — Saccocoma — Pianella grudii et Charophytes — «Macroporella» sellii — «Lituonella» sp. — Clypeina jurassica, et — Calpionelles. GINIEN)^ INTERM£DIAIRES: JURASSIQUE-CRfiTACe (INFRAVALAN-Les microfacies a — Clypeina jurassica et Tintirmines aberrantes, et — Calpionellopsis, Tintinnopselles et Calpionelles peu frequentes. A cote des microfacies cites on a observe que les microfacies a Pseudocodium convolvens (pi. 9/2, pi. 10/1, Bullopora sp. (pi 104) et Clypeina spp. (pi. 35 et 36) out egalement une extension stratigraphique tres restreinte. Leur valeur stratigraphique ne pouvait pas etre verifiee etant donne qu'ils ne sont pas constates, dans le cadre des etudes faites jusqu'a present, que dans les series ici presentees. En terminant il faudrait souligner que l'etude des microfacies juras-siques est faite grace a nombreuses observations sur le terrain, C'est ce qui a permis d'observer beaucoup plus facile la migration des fades dans le temps et espace dont il faudrait tenir grand compte a l'occasion de 1 interpretation stratigraphique. Je citerais un exemple: les calcaires a Elhpsactinia des zones paleogeographiques determdnees des Dinarides externes apparaissent dans le Malm inferieur, tandis que les calcaires a Elhpsactinia d'autres zones ayant la position des falaises par rapport aux sillons de ce miogeoeynclinal (par rapport au sillon de Budva-Boka ou celui au Nord: la falaise a peu pres de la ligne Vjetarnik-Durmitor-Nevesinje) sent sans doute plus jeunes — ils se trouvent dans le Malm superieur. * Les lames minces micropaleontologiques appartiennent a la Collection des lames mances micropaleontologiques de l'lnstitut de recherches eeo-logiques et gecphysiques a Belgrade. ¥ Etant donne qu'aux domaines examines apres le Juras&ique sud s etaient continument deposees les couches cretacees inferieures& cote des microfacies jurassiques de certaines series on presite egale^lnt le micrt facaes infravalanginiens et valanginiens infčrieurs. la sfcrie jurassique des versants nord de la montagne rumija Age Facias Planche X« Krsajina de l'Est Krajina de 1'Ouest Trias Lias Dogger Malm Neocomden superieur inferieur 1 superieur Calcaires a Tintinnines aberran-tes et autres microfossdies. Do-lomies. Calcaire a Clypeina jurassica, autres Dasycladacees et Forami-(Jurassique superieur de niferes. Dolomies. la Krajina d© l'Est n'est pas etudie.) Calcaires a Cyanophytes, Conico- spirillina, Pseudocyclammina, Di- , . , . ceras, Nerin£id£s et rares Clado-Calcaires organogfcnes et ^ organogenes-detntiques a Hydrozoaires, Poly- piers, etc. Calcaire or- Calcaires massifs biohermes a ganogene-detritique avec polypiers coloniaux; Ellipsacti-petits morceaux de nia, autres Hydrozoaires, Diceras jaspes. et Nerineides. i Calcaires orgainog£nes-detritiques * k Gasterapodes, Polypiers solitaires, Hydrozoaires, Pseudoco-dium coiiv-olvens, autres Algues et Protopeneroplis striata Breche heterogene (les Calcaires oolithiques a Trocho-composantes: calcaires lines, Protopeneroplis striata, ra-liasiques varies et res Dasycladacees et autres jaspes). Algues. Calcaires oolithiques et oolithi- t ques-detritiques a Echinodermes, « , , . Laeenides, Vidalina et autres Calcaires a jaspes (Bra- Fo®aminif-res. chiopoaes) et zones a jaspes. i Calcaire a Orbitopsella et autres Foraminiferes, calcaire k Palaeo-4, dasycladus mediterraneus. Dolomies et calcaires a Megalodontides. 16 & 18 13 ž 15 11, 12 10/2 10/1 8, 9 7/2 6, 7/1 5/2 5/1 4 3 2 1 LA SČRIE JURASSIQUE DE LA BORDURE OUEST DE LA ZETSKA RAVNICA ET DU DISTRICT VERS L'ANCIEN MONTENEGRO Age F a c i 6 Planche Ni § «.2} -h c-< i/i Calcaires a Tintmnines aberrantes; calcaires k Coprolithes, Dasycladacees, etc.; calcaires dolomitiques et dolomies. C ale aire a Tintinnines aberrantes ©t Clypeina jurassica. Dolomies. Dolomies, calcaires dolomitiques et calcaires a Clypeina jurassica (pro parte, dans la partie inferieure: calcaire k Charophytes). Calcaire k Kurnubies, Cyanophytes, Hydrozoai-res, etc.: dolomies. Calcaire a Clypeina spp., Kurnubies, etc. Caloadires a Cladocoropsis mirabilis, Kurnubies, Pseudocyclammina, Cyanophytes et Dasycladacees. Pro parte, dans la partie inferieure: calcaire oolithique a Trocholines. Calcaiire divers, grumeleux et organogene-det-ritique a Pfenderinides, Trochammimd^s, Textularides, Verneuilinides et Dasycladac£e Teutloporella gallaeformis. Calcaire oolithique a Protopeneroplis striata. Calcaires k Selliporella donzellii, Teutloporella gallaeformis et autres Dasycladacees, puis Trochamminid6s, Textularides, Verneuilinides, etc. Calcaire oolithique k Protopeneroplis striata. Calcaire a Dictyoconus cayeuxi. Calcaires a Trochammdnides, Textularides, etc. Calcaire grumeleux k Thaumatoporella. Calcaires oolithiques; calcaire a Glomospira et Codiacees; calcaires k Lithiotis, Pseudocyclammina, Lituosepta, Orbitopsella et Pa-laeodasycladus. Calcaire a Palaeodasy- , cladus mediterraneus. uoiomies. Dolomies et calcaires k Megalodontides. 41 39, 40 38 35 i 37 34/2 34/1 33 32 31 30 29 28 27 26 25 24 23 20 a 22 19 LA SfiRIE JURASSIQUE DE LA BORDURE NORD DE LA ZETSKA RAVNICA DISTRICT DE DEClC ET DE CIJEVNA Age Facias Planche Malm N 60 c o mien inferieur 1 superieur Calcadre peu bitumineux a Tin-tinnines aberrantes, Coprolithes, Salpingoporella annulata, Gaste-ropodes, etc. Calcadre peu bitumineux a Cly-peina jurassica, Tin tannines aberrantas et Salpingoporella annulata. Dolomies, calcaire dolomitiques et bitumineux et calcaire a Clypeina jurassica. t Calcaire k Cha- Calcaire a rares Calcaires organogenes rophytes, Ostra- Clypeines, «Macro- et organogenes-detri-oodes, Pianella porella» sellii et tiques a Hydirozoaires, jrudii et Ostr£- Cyanophytes, «Li- Polypiers, Brachiopo-tuonella», Kurnu- des, Nerinčes et Di-bia, etc. ceras. Calcaire a Cladocoropsis mirabilis, Calcaires oolithiques Cyanophytes, «Macroporella» sellii, et oolithiques-d6triti-Kurnubies et autres Foraminiferes, ques a Protopenerop- lis striata et rares Cladocoropsis, calcaire h Codiacees. 55 54/2 54/1 49 k 53 46 A 48 45/2 45/1 44 42, 43 Tableau Jfc4 LA SfiRIE JURASSIQUE DE LA MONTAGNE VOJNIK Age F a c i h Planche JSfe Calcaires a Tin tin nines aberrantes, Coprolithes. Dasycladac6es, Nerinees, etc. Calcaire a Clypeina jurassica et Tintinnines aberrantes. Dolomies. Calcaire a Clypeina jurassica. Dolomies. 72 Calcaiires orga-nogenes et or-ganogeno-detri-tiques š Hydro-zoaires, Poly-piers, Diceras, Nerineides, etc. Calcaire marneux k Ostracodes, Cha-rophytes et Pumella grudii. Niveau du calcaire conglomeratique et de celui d'aspect conglomeratique et traces de bauxite. Bauxite Calcaire organoge-no-dčtritique a Hydrozoaires, Po-lypiers, etc. Calcaires organogdno-detritiques a Trocholines et Protopeneroplis striata. Dolomies. Calcaire a Lamellibranches pčlagi-ques, calcaire a Globiig§rines. Micro-breche. w ^ cc v —■ u u -flj M Calcaire mairneux rougeatre et calcaire a La-genides, Spirillina liassica et C<§phalopodes. Marno-calcaire et calcaire marneux a Lageni-des et Spirillina liassica. Dans la partie inferieure: calcaire a Triassina hantkeni. Dolomies et calcaires a Megalodotntid^s. LA SERIE JURASSIQUE DE KOSANICA ET DE KRALJEVA GORA Age F a c a k s Planche Jfs s i Z Calcaire marneux et mamo-calcaire k Cal-pionella, Calpionellopsis et Tintinnopsella. 79 u 1 Malm infer. supi La serie clastique — calcaire marneaux h Calpionella et Radial aires, marne, calcareni-tes, calcadres brechiques, etc. Calcaires organogfcnes et organogenes-de tri t i-ques a Mollusques, Polypiers, Hydrozoaires 78 77 76 75/2 t_i et Codiacees. o> Ofi Ofi 0 Q Calcaires divers k petits Foramiriiferes et Aeolisaccus. 75/1 Calcaires rougeatres et grisatres k Globo-chaete, Lagčnides, Lamellibranches p61agi-ques, etc. 74/2 Lias Calcaire rouge a Lagenides, Vidalina martana, Spirillina liassica et Cephalopodes. 74/1 Calcaires grisatres a Thaumatoporella et Aulotortus. 73 Trias superieur Calcaire k Megalodon tides. 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Beograd 1963. Radoičič R., 1962, Bilješka o dogeru spoljašnjih Dinarida. Zapisnici SGD za 1962. Beograd. Radoičič R., 1962, Gornja jura sjeverne Hercegovine. Zapisnici SGD za 1962. Beograd. Radoičič R., 1962, Hadžiella zetae gen. nov. sp. nov. aberantnih tin-tinina. Zapisnici Srp. geol. društva za 1962. g. Beograd. Radoičič R., 1962, Paleoekologija i biostratigrafija aberantnih tintinina Jugoslavije. Disertacija, Ljubljana 1962. Radoičič R., 1963, Mikrofauna gornjolijaskih krečnjaka Črne Gore, Stare Raške i Rožaja. Vesnik Zavoda za geol. i geof. istraživanja u Beogradu knj. 20. Beograd. Radoičič R., 1963, O jednoj novoj gornjojurskoj dazikladacei Pianella grudii gen. nov., spec. nov. Vesnik Zavoda za geol. i geof. istraživanja u Beogradu, knj. 20. Beograd. Radoičič R., 1964, Mikropaleontološke odlike i stratigrafska korelacija nekih jurskih stubova spoljašnjih Dinarida. Referat na Simpozijumu za naftu maja 1963. u Hercegnovom. Nafta, br. 10. Radoičič R., 1964, Teutloporella gallaeformis spec. nov. iz jure spoljašnjih Dinarida. Geološki glasnik Zavoda za geol. istraživanja u Titogradu knj. IV (u štampi). Raff i G., F or t i A., 1959, Micropaleontological and stratigraphical investigations in «Montagna del Morone» (Abruzzi — Italy). Revue de Micro-pal eontologie, vol. 2, n. 1. Paris. R e m a n e J., 1958, Quelques observations sur la passage des fades sub-alpins a la limite jurassique-cretace dans les environs de Grenoble. Trav. du Lab. Geol., Fac. Sc. Univ. Grenoble, t. 34, Grenoble. Re ma ne J., 1964, Revision paleontologi que de Tintinnopsella oblonga (C a d.) et des especes avoisinantes (Note preliminaire). Revue de M ic ropal eon tologie, vol. 7, n. 1. Paris. Rutgers A. Th. C., 1942, Geologie und Paleontologie des sudostliche en Teiles des Biokovo und seines Hinterlandes (Dalmatien). Geogr. en Geol. Me-dedeelingen, ser. 2, n. 4, Utrecht . Sar t on i S., Crescent i U., 1959, La Zona a Palaeodasycladus me-diterraneus (P i a) nel Lias dell'Appennino meridionale. Giorn. di Geol., ser. 2, vol. 27 (1956-57). Bologna. Sartoni S., Crescenti U., 1962, Ricerche biostratdgrafiche nel mesozoieo dell'Appennino meridionale. Giorn. di Geol., ser. 2, vol. 29 (1960-61). Bologna. S i g a 1 J., 1952, Ordre des Foraminifera in: P i v e t a u : Tradte de Paleontologie, vol. 1. Paris. S m o u t A. H., S u g d en W., 1962, New information on the foramini-feral genus Pfenderina. Paleontology, vo. 4, n. 4. London. S i r n a G., 1962, Stratigrafie e microfacies dei lembi mesozoici della valle di Galati Mamertino (SiciLia nord-orientale). Geologica Romana, vol. 1. Roma. Y a b e H., T o y a m a S., 1949, New Dasycladaceae from the Jurassic Tori-nosu Limestone of the Sakawa Basin II. — Proceed, of the Japon Acd., vol. 25, 7. Weynschenk R., 1951, Two new Foraminifera from the Dogger and Upper Tniassic of Sonnwend Mountains of Tyrol. Jour. Pal. vol. 25, n. 6. Tulsa. Weynschenk R., 1956, Some rare Jurassic index Foraminifera. Micro-paleontology, vol. 2, n. 3. New York. LISTE DES PLANCHES La serie jurassique des versants nord de la montagne Rumija...................I—XVIII La serie jurassique de la bordure ouest de la Zetska ravnica et du district vers l'Ancien Montenegro .... XIX—XLI La serie jurassique de la bordure nord de la Zetska ravnica — district de Dečič et de Cijevna......XLII—LV La s^rie jurassique de la montagne Vojnik......LVI—LXXII La serie jurassique de Kosanica et de Kraljeva gora . . LXX1II—LXXIX La serie jurassique des environs de Plevlja — Dinarides internes...................LXXX—LXXXVIII La serie jurassique de l'Herzegovine du sud — district entre Dubrovačko primorje et Trebinje—Popovo polje . LXXXIX—CIX La serie jurassique de la region Mosor—Biokovo—Bačine CX—CXXI La serie jurassique de Lemeš et de ses environs .... CXXII—CXXXIII La serie jurassique des environs de Rovinj......CXXXIV—CXLI La serie jurassique des environs de Sošice (Zumberak) . CXLII—CXLVIII Les autres microfacičs jurassiques..........CXLIX_CLXV 1. Foraminifera EXTENSION STRATIORAPHIQUE PES FOSSILS JURASSiaUES PES DIVIDES EXTERNES DE LA YOUGOSLAVIE Permodiscus sinuosus (W e y ri s c li e 11 k|- Triassina hantkeni M a j z o n Vidalina martana Farinacci ...... Tetrataxis conica E h r c m b c r k Glomospira spp.......................................................... Lagenidae............................................................. Spirillina liassica (Jone s) .......................... Spirillina spp..................................................... Trocholina cf. conica (S c h 1 u m b. )................ Trocholina sp. nov............................................ Haurania amiji H e n s o n................................. Orbitopsella praccursor (Gumbe 1)............... Lituosepta recoarensis C a t i ........................ Ophtalmidium cf. macfadyeni Wood & bar. Pseudocyclammina spp. .............................................. "Trochaminidae" ................................................................ "Textulariidae" ............................................................. "Vemeuilinidae" ........................................................ Dictyoconus caycuxi Lucas ............................. Globigerina helveto-jurassica H a c u s a...... Endothjyra sp................................................................ Trocholina alpina (Leu p)................................... Trocholina elongata (Leu p.)............................. Trocholina spp........................................................... Protopeneroplis striata Weynschenk •• Pfenderina salernitana Sart. & C r c s c. Pfenderina trochoidea Smout & Su g......... Meyendorffina bathonica Aur. & Bizon- Pseudocyclammina lituus (Y o k o y a m a) ....... Kurnubia palastiniensis H e n s o n ................ Kurnubia wellingsi (H e n s o n) ......................... Nautiloculina cf. oolithica M o h 1 e r........... Conicospirilina basiliensis M o h 1 e r .......... Labyrinthina mirabilia Weynschenk-... Bullopora spp......................................................... "Lituonella" sp. ................................................ D 0 G G E R M INFČRIEUR L M SU PERlE UR N t O C VAL AN GIN IE N 0 M I E N I HAUTERIVIEN — csptec cbonctanU — cftptcc ror* npice present« 2. Algae, Microproblematica, Tintinnina, etc. EXTENSION STRATIGRAPHIQUE DES FOSSILS JURASSIQUES DES ClNARlDES EXtERNES OE LA YOUGOSLAVlE L IAS 0 O G G E R MALM 1NFERIEUR | | SUPERlEUR NEOCOMIEN VALANGINIEN I HAUTERIVIEN Thaumatoporella parvovesiculifera (Rain.) Sestrosphaera Hasina P i a .................................. Palaeodasycladus mediterraneus P i a .............. Selliporella donzellii Sart. & Cresc Dazikladacea D4 .......................................................... Dazikladacea D25 ........................................................ "Macroporella" sellii Crescenti. ........ Petrascula bursiformis E t t a 1 o n ............. Clypeina spp............................................................... Clypeina jurassica F a v r e ......................... Salpingoporella annulata C a r o z z i .......... Charophyta ........................................................................ Pianella grudii Radoičič ....................... Pianella pigmaea P i a ......................................... Pianella gigantea C a r o z z i ......................... Teutloporella obsoleta C a r o z z i ............... Cyanophyta............................................................... Codiaceae: Cayeuxia, etc....................................... Codiaceae CI .......................................................... Boueina-Halimeda ...................................................... Bačinella irregularis Radoičič ........... Pseudocodium convolvens Praturlon Microproblematica Pr.................................................. Microproblematica Pr ............................................... Bryozoaire (?) - B1 ................................................. Aeolisaccus spp................................................... Prethocoprolithus centipetalus Elliot- Favreina salevensis (P a r e j a s)................. Cladocoropsis mirabilis Felix .................. Ellipsactinia spp...................................................... Annelides.............................. .................................. Saccocoma A g a s i z ............................................. Globochaete alpina Lombard ....................... Calpionella alpina L o r c n z ....................... Oalpionella elliptica C a d i s c h................ Tintinnines aberrantes................................................. especa abondant« esptcc rar« ----«spic« prfs«nt« LA S&RIE JURASSIQUE DES VERSANTS NORD DE LA MONTAGNE RUMIJA (Tableau Jfe 1) Planches: I & XVI11 2 — Geologija St. 9 Fig. 1 et 2 Calcaire grumeleux, en partie subcristallin, k Palaeodasycladus mediterraneu& Pia (X17). PI. mince 3069—60. Dans l'association: petits Foraminiferes neu abondants Montagne Rumija, versants nord, Krajina de l'Ouest LIAS INFfiRIEUR Les calcaires a Palaeodasycladus sont souvent tachetes quodque ce ne soit pas lei le cas. Ces taches grandes de 0,5 k 1,5 mm sont de fait les Cyanophytes dont le noyau renferme d'ordinaire des Palaeodasycladus. Dans ces cas ils sont tenement mal preserves («dissolus») que leur construction k peine s'apercoit dans la lame mince Fig. 1 Calcaire a Frondicularia sp. et Radiolaires (X 37,5). PI. mince 3070-60 Versants nords de la montagne Rumija, Krajina de l'est LIAS INF£rieur-mo yen (sčrle des calcaires et jaspes) Fig. 2 Calcaire legerement marneux š Frondicularia sp. (X 37,5). PI. mince 3071-C0 Versants nords de la montagne Rumija, Krajina de l'est LIAS iNFftRIEUR-MO YEN (sčrip des caLcairea et Jaspes) Fig. 1 et 2 Calcaire grumeleux a Orbitopsella, petits Foraminiferes, Thaumatoporella et fins debris organogenes (X 27,5). PI. mince 3072-60 Versants nords de la montagne Rumija, Krajina de l'ouest LTAS MOYEN Fig. 1 Calcaire oolithique a debris d'Echinodermes (X 27). PI. mince 3074-60 Versants nords de la montagne Rumija, Krajina de l'ouest LIAS SUPERIEUR Fig. 2 Calcaire organogene-detritique a Lagenides (Cristellaria sp. et autres), Vidalina martana Farinacci, Microgasteropodes et debris d'Echinodermes (X 27,5). PL mince 3077-60 Versants nords de la montagne Rumija, Krajina de l'ouest LIAS SUPERIEUR (LIAS SUPEHIEUR-DOGGER INFERIEUR) Fig. 1 Calcaire microgrumeleux a Ophtalmidium sp. et fins debris organogenes (X 27,5). PI. mince 3077-60; le meme plaque mince: pi. IV, fig. 2 Versants nords de la mootagne Rumija, Krajina de l'ouesit LIAS SUPERIEUR (OU LIAS SUPERIEUR-DOGGER INFERIEUR) Fig. 2 Calcaire grumeleux, organogene^d6tritique, k Trocholines, Lituolides et autres Foraminifčres (X 35). PI. mince 03460 Versants nords de la montagne Rumija, Krajina de l'ouest DOGGER INF2RIEUR Fig. 1 Calcaire a Codiacees ert rares Foraminiferes (X 17,5). PL mince 3078-60 Versants nords de la montagne Rumija, Krajina de 1'ouest DOGGER Fig. 2 Calcaire oolithique a debris de Dasycladacee Selliporella donzellii Sartoni & Crescenti (X 30). PI. mince 3079-60. Dans l'association: Trocholina, Endothyra et autres Foraminiferes Versamts nords de la montagne Rumija, Krajina de 1'ouest DOGGER SUPfiRIEUR Fig. 1 Calcaire oolithique k Protopeneroplis striata Weynschenk et Trocholines (X 40). PI. mince 3083-60 Versants nords de la montagne Rumija, Krajina de 1'ouest DOGGER SUPERIEUR Fig. 2 Calcaire k Nerineides (X 15). PI. mince 3084-60 Versants nords de la montagne Rumija, Krajina de 1'ouest DOGGER SUPfiRIEUR — MALM INFfiRIEUB Fig. 1 v Calcaire a Thaumatoporella parvovesiculifera (Rain.) (X 27,5). PI. mince 3085-60. Dans l'association: Bačinella, rares Trochollnes et mal conserves et <'dissolus» CladocoTpsis Versants nords de la montagne Rumija, Krajina de l'ouest MALM INFERIEUR (les couches les plus anciennes) Fig. 2 Calcaire organogene-detritique k Pseudocodium convolvens Praturlon et petits Foraminiferes (X 27,5). PI. mince 3089-60. Dans l'association: Bačinella irregularis RaxJoičič et autres Codiacees, Pseudocyvlammina, Polypi ers, Hydrozoaires et dšbris d'Echinodermes Versants nords de la montagne Rumija, Krajina de l'ouest MALM INFERIEUR (les couches les plus anciennes) Fig. 1 Calcaire pseudooolithique^detritique k Polypiers; Trocholines et autres Forami-niferes (X 17,5). PI. mince 3088-60. Dans Passociation: Protopeneroplis striata Weynschenk, Pseudocodium convolvens Praturlon, etc. Versants nords de la montagne Rumija, Krajina de l'ouest MALM INFfiRIEUR (les couches les plus ancienn.es) Fig. 2 Calcaire organogene-detritique a Pseudocyclammina lituus (Yokoyama), Pseudocodium convolvens Praturlon, etc. (X 27,5). PI. mince 3090-60 Versants nords de la montagne Rumija, Krajina de l'ouest MALM INF6RIEUR (les couches les plus aneiennes) Fig. 1 Calcaire organog6ne-dčtritique k Pseudocodium convolvens Praturlon (X 27,5). PI. mince 3090-60 Versants nords de la montažne Rumija, Krajina de l'ouest MALM INFfiRIEUR (les couches les plus anciennes) Fig. 2 Calcaire a Foraminiferes peu nombreux (Miliolides et autres), debris de Mol-lusques, d'Echinodermes et d'Algues (X 27,5). PL mince 3092-60 Versants nords de la montagne Rumija, Krajina de l'ouest MALM INFfiRIEUR (probablement OXFORDIEN) Fig. 1 et 2 Calcaire legereanent marneux k Cyanophytes (Girvanella ?), (x 17,5). PI. minces 2312a et 2312 b-60 Versants nords de la montagne Humija; Krajina, Muriči MALM (OXFORDIEN-KIMMfiRIDGIEN) Fig. 1 et 2 Calcaire fin microgrumeleux a Conicospirillina basiliensis Mohler, Pseudo-cyclammina sp. et autres rares Foraminiferes; Prethocoprolithus centripetalus Elliott, Cyanophytes, etc. (X 27). PI. mince 2321-60 Versants nords de la montagne R umi j a, Krajina, environs de Muriči MALM (KIMMfiRIDGIEN INFfiRIEUR) Fig. 1 et 2 Calcaire lčg&rement marneux k «Lituonella» et Cyanophytes (X 27,5 — fig. 1; X 17,5 — fig. 2). PI. minces 2316 et 2315-60. Dans l'association: tres rare Clype\-na jurassica Favre, Thaumatoporella parvovesiculifera (Rain.) et Codiac£es (= pi. XIV) Versants nords de la montagne Rumija, Krajina, environs de Muriči MALM SXJPfiRIEUR (KIMMfiRIDGIEN SUPfiRIEUR) Fig. 1 et 2 Calcaire k Thaumatoporella parvovesiculifera (Rain.), Codiacees et «Lituonella» (X 27). PI. mince 2315-60 Versants nords de la montagne Rumija; Krajina, Muriči MALM SUPERIEUH (K1MMERIDG1EN SUPERIEUR) Fig. 1 Calc&ire k Pseudocyclammina cL lituus (Yokoyama), (X 27,5). PI. mince 2314-60. Dans 1'association: Cladocoropsis mirabilis Felix. Versants nords de la montagne Rumija; Krajina, Muriči MALM SUPERIEUR (K1MMERIDGIEN SUPERIEUR) Fig. 2 Calcaire a Cladocoropsis mirabilis Felix (X 27). Pl. mince 2314-60 Versants nords de la montagne Rumija; Krajina, Muriči MALM SUP£KIEUR (KIMMERIDGIEN SUPERIEUR) Fig. 1 Calcaire a Clypcina jurassica Favre (X 27,5). Pi. mince 2312-60. Dans l'associa-tioai: Cyanophytes. Ostracodes et tres rares petits Foraminifšres Versants nords de la montagne Rumija; Krajina, Muriči MALM SUPERIEUR (KIMMERIDGIEN SUPERIEUR-PORTLANDIEN) Fig. 2 Calcaire k Charophytes (X 27,5). PI. mince 2311-60. Dans 1'association: Ostracodes Versants nords de la montagne Rumija; Krajina, Muriči MALM SUPERIEUR (KIMMERIDGIEN SUPERIEUR-PORTLANDIEN) Fig. 1 et 2 Calcaire oolithique-detritique k Nerinea cL suesst Peters* et Codiacees (X 15). PI. mince 2310-60 Versants nords de la montagne Bumija; Krajina, Muriči MALM SUPERIEUR (PORTLANDIEN) • Determination de Mme. O. Markovi č. Fig. 1 et 2 Calcaire legerement marneux a Salpingoporella annulata Carozzi, une Dasy-cladacee inconnue (D27) et Mollusques (X 27,5). PI. mince 2309-60. Dans l'association: Clypeina jurassica Favre, autres Dasycladacees, Kurnubia et rares Polypiems solitaires Versants nords de la montagne Rumija; Krajina, Murici MALM SUPERIEUR (PORTLANDIEN) m, % % r i o 4* LA S£RIE jrRASSIQUE DE LA BORDURE OUEST DE LA ZETSKA RAVNICA ET DU DISTRICT VERS L'ANCIEN MONTENEGRO (Tableau J^ 2) Planches: XIX k XLI Fig. 1 et 2 Calcaire k Palaeodasycladus mediterraneus Pia et petits Foraminiferes (X 17) PI. mince 1229-57 Odrinska gora (rile dans le lac Skadarsko jezero) lias infčrieur Fig. 1 et 2 Calcaire microgrumeleux a Orbitopsella praecursor (Gumbel), (x 17,5). PI. minces 1815 et 1816-60 Bordure ouest de la Zetska ravnica, Dodoši lias moyen Fig. 1 et 2 Calcaire legerement marneux a «Aeolisaccus» (dčbris de Bryozoaires?), Bryo-zoaires et tr£s transformees Dasycladacees-Palaeodasycladus mediterrancus Pia (X 40). PI. mince 353-55 Bordure ouest de la Zetska ravnica, Dodoši lias moyen Fig. 1 Calcaire legerernent bitumineux a Pseudocyclammina sp., autres Foramini-feres et debris de Mollusques (X 40). PI. mince 197-55 Bordure ouest d© la Zetska ravnica, Dodoši lias moyen Fig. 2 Calcaire bitumineux a Pseudocyclammina sp. et les coques des petites Lamelli- branches (X 40). P. mince 351-55 Bordure ouest de la Zetska ravnica, Dodoši lias moyen Fig. 1 Calcaire marneux, peu bitumineux, a Lituolides et autres Foraminiferes, Micro-gasteropodes et debris de Mollusques (X 17,5). PI. mince 354-55 Bordure ouest de la Zetska ravnica, Dodoši LIAS MOYEN Fig. 2 Calcaire a Codiacees fx 17,5). PI. mince CG-1106. Dans l'association: Thauma-toporella parvovesiculifera (Rain.) et petits Foraminiferes L'Ancien Montenegro, Topsude lias moyen-superieur Fig. 1 Calcsire microgrumeleux a Thaumatoporella parvovesiculifera (Rain.) et rares petits Foraminifcres (X 29). PI. mince 1819-59 Bordure ouest die la Zetska ravnica, Buza-Bobija lias superieur-dogger inferieur Fig. 2 Calcaire grumeleux a Trochamminides et Textularides (X 29). PI. mince 1820-60. Dans l'association: rares Codiacees et Microgasteropodes Bordure ouest de la Zetska ravnica, Buza-Bobija lias superieur-dogger inferieur Fig. 1 Calcaire peu detritique, subcristallin, a Trochamminides, Verneuilinides, Textu-larides et tres rares MiLiolidšs (X 28). PI. mince 1822-60. Dans l'association: Thaumatoporella parvovesiculifera (Rain.) et rares petits Trocholines Bordure ouest cie la Zetska ravnica, Buza-Bobija DOGGER INFERIEUR Fig. 2 Calcaire a Foraminiferes peu abondants, Aeolisaccus sp. et Microgasteropodes (X 28). PI. mince 1823-60. Dans l'association: Thaumatoporella parvovesiculifera (Rain.) Bordure ouest de la Zetska ravnica, Buza-Bobija dogger inffirietjr Fig. 1 Calcaire grumeleux, en partie oolithique, a Dictyoconus cayeuxx (Lucas), (X 37,5). PI. mince 615-61 L'Ancien Montenegro, environs de Grkavac dogger inferieur Fig. 2 Calcaire oolithique-detritique a Dictyoconus cayeuxi (Lukas), (X 37,5). PI. mince 621-61 L'Ancien Montenegro, environs de Resna dogger inferieur Fig. 1 Calcaire organogžne k Tex tula rides, Trochamminides, Verneuilinidšs, puis Thaumatoporella parvovesiculifera (Rain.), Dasycladacees et debris divers (X 17,5). Pl. mince 1824-59 Bordure ouest de la Zetska ravnica, Buza-Bobija dogger inferieub Fig. 2 Calcaire organogene a nombreux Foraminiferes (Textularides, Trochamminides, Verneullinidcs, lVliliolides, etc.), et debris de Mollusques (X 28,5). PI. mince 1827-59. Dans l'association: Dasycladacees et petites Nerinella Bordure ouest de la Zetska ravnica, Buza-Bobija dogger superieur Fig. 1 et 2 Calcaire organogčne k Thaumatoporella parvovesiculifera (Rain.), nombreux Foraminifdres (Trochamminides, Textularides, Verneuilinid6s et aut.) et debris tres abondants de Dasycladacees (Selliporella) et de Mollusques (X 28,5). PL mince 1827-59 Bordure ouest de la Zetska ravnica, Buza-Bobija dogger superieur Protopeneroplis striata apparaissant gčnčrailement dans les calcaires oolithiques et oolithiques-dštritiques est peu frequente dans les sediments de la bordure ouest de la plaine Zetska ravnica ou les calcaires oolithiques apparaissent secon-dairement dans le Dogger et Malm. Dans la oolonne examinee les Protopeneroplis sont observes dans une couche des calcaires oolithiques dčtritiques se trouvant k quelques metres au-dessus du calcaire presents sur cette planche. Fig. 1 Calcaire phytogene k Selliporella donzellii Sartoni & Crescenti et Foraminife- res tres rares (X 40). PI. mince 167-57 Bordure ouest de la Zetska ravnica, au nord de Ponar dogger superieur Les microfacies des calcaires k SelUporella donzellii ou leurs dčbris et autres microfossiles peu frequents, repr^sentent, ayant en vue leur large extension geographique, les microfacies du Dogger les plus importants dans les Dinari-des ex tern es. A cote de Tesp^ce Selliporela donzellii se trouvent de plus deux Dasycladac^es: Tevtloporella gallaeformis Rad. et la D4. Fig. 1 Calcaire grumeleux k Thaumatoporella parvovesiculifera (Rain.) et Foramini-feres (X 28,5). PI. mince 1828-59. Dans l'association: debris de Dasycladac6es, rares Microgasteropodes et Polypiers Bordure ouest die la Zetska ravnica, Buza-Bobija dogger superieur Fig. 2 Calcaire grumeleux a Pfenderina salernitana Sartoni & Crescenti (X 30). PI. mince 1834-59. Dans l'association: autres Foraxnini feres peu abondants et debris de Dasycladacees Bordure ouest de la Zetska ravnica, Buza-Bobija dogger supjsrieur-malm infekleur Fig. 1 et 2 Calcaire a Pfenderina cf. trochoidea Smout & Sugden, Meyendorffina bathonica Aurouze & Bizon et autres Foraminiferes (X 28,5). PI. mince 1834-59 Bordure ouest de la Zetska ravnica, Buza-Bobija dogger superieur-malm inffirieur Fig. 1 et 2 Calcaire a Pfenderines (Pfenderina sp.), Verneuilinides, Textuiarides et autres Foraminiferes (X 30). PI. mince 1841-59. Dans l'associations: Thaumatoporella parvovesiculifera (Rain.), Teutloporella gallaeformis Radoičič, Microgastero- podes et debris de Mollusques Bcrdure ouest de la Zetska ravnica, pres de Ponar dogger supfirieur-malm inferieur Fig. 1 Calcaire oolithique-detritique a Trocholines, Labyrinthina mirabilis Weynschenk et autres Foraminiferes (X 17). PI. mince 44-57 Bordure ouest de la Zetska ravnica, Kurioei-Vukovci MALM INFERIEUR (parUe iničrieure des couches k. Cladocoropsis mirabilis) Fig. 2 Calcaire oolithique-detritique a Trocholines (X 17). PI. mince 133a-57 Bordure ouest de la Zetska ravnica, Kurioci-Vukovci MALM INFERIEUR Fig. 1 Calcaire a Cladocoropsis mirabilis Felix (X 10). PI. mince 137-57 Bordure ouest de la Zetska ravnica, au sud de Vukovci MALM INFERIEUR (KIMMERIDGIEN INFERIEUR) Fig. 2 Calcaire a Kurnubia palastiniensis Hens on, autres Foraminiferes et Dasycladacees (Clypeina spp. et autres), (X 30). PI. mince 1095-57 Bordure ouest de la Zetska ravnica, Rvaši MALM SUFERIEUR (partie infčrieure des couches & Clypeina jurassica) Fig. 1 et 2 Calcaire š Dasycladacees (Ctyjieina spp. et autres), (X 30). PI. mince 1095-57 Bordure ouest de la Zetska ravnica, Rvašd MALM SUPfiRIEUR (partie lnfčrleure des couches k Clypeina jurassica) Fig. 1 et 2 Calcaire a Dasycladacecs (Clypeina spp. et autres) et Foraminifčres peu abon- dants (X 30). PI. mince 1095-57 Bo-rdure ouest de la Zetska ravnica, Rvaši MALM SUPŽRIEUR (partie inf6rieure des couches d Clypeina ^urassico) Fig. 1 Calcaire a Kurnubia sp. ©t Dasycladacees (X 35). PL mince 1096-57 Bo rehire ouest de la Zetska ravnica, Rvaši MALM SUPfiRIEUR (partie inf6rieure des couches k Clypeina jurassica) Fig. 2 Calcaire a Kurnubia wellingsi (Henson), Kurnubia sp. ©t autres Foramini feres (X 30). PL mince 1097-57 Bordure ouest de la Zetska ravnica, Rvaši MALM SUPERIEUR (partie inferieure desi couches k Clypeina jurassica) Fig. 1 Calcaire marneux, peu bitumineux, a Charophytes (X 28,5). PI. mince 1851-59 Bordure ouest de la Zetska Ravnica, Bobija MALM SUPfiRIEUR (partie inlčrieure des couches k Clypeina jurassica) Fig. 2 Calcaire marneux a Ostracodes (X 70). PI. mince 1099-57 Bordure ouest de la Zetska ravnica, Rvaši MALM SUPfiRlEUR (partie infčrieure des couches a Clypeina jurassica) 102 Fig. 1 Calcaire a rhombočdres de dolomie, Clypeina jurassica Favre et Kurnubia palastiniensis Henson (X 30). Pl. mince 55-57 Bordure ouest de la Zetska ravnica, Vukovci MALM SUPERIEXm (PORTLANDIEN) FUg.2 Calcaire a Pianella cf. gigantea Cairozzi, Salpingoporella annulata Cairozzi et Clypeina jurassica Favre (X 30). Pl. mince 139-57 Bordure ouest de la Zetska ravnica, Vukovci MALM SUPfiRIEUR (PORTLANDIEN) Fig. 1 Calcaire marneux k Clypcina jurassica Favre et Teutloporella obsoleta Carozzi (X 17,5). PI. mince 159-37 Bordure ouest de la Zetska ravnica, Vukovci malm supfirieur (portlandien) Fig. 2 Calcaire legerement marneux et dolomitique & Clypeina jurassica Favre (X 17,5). PI. mince 160-57 Bordure ouest de la Zetska ravnica, Vukovci malm superieur (portlandien) Fig. 1 Calcaire a Tintinnines aberr&ntes — (Daturellina costata Rad.) — et Salpingo-porella annulata Carozzi (X 27,5). PI. mince 289-55 Bordure ouest de la Zetska ravnica, Trstenik valanginien inferieur LA SERIIS JURASSIQUE DE LA BORDURE NORD DE LA ZETSKA RAVNICA DISTRICT DE DEClC ET DE CIJEVNA (Tableau Ks 3) Planches: XLII a LV Fig. 1 et 2 Calcadre oolithique-detritique a Protopeneroplis striata Weynschenk et Codiacee CI (fig. 1 — X 82; fig. 2 — X 32). PI. mince 1197-57. Dans l'association: Trocho-lines, rares Miliolides et autres Foraminiferes, Cladocoropsis mirabilis Felix. Bordure nord de la Zetska ravnica — canon de la riviere Cijevna, au sud de Stepovo. MALM INFERIEUR 8 — Geologija št. 9 113 Fig. 1 Calcadre oolilhicue-detritique a Protopeneroplis striata Weynschenk et Nau-tilocahna sp. (J. Speck: «Nautiloculina n. sp. aff. oolithica M6hler»), (X 60). Pl. mince 1198 a-57 Bordure nord de la Zetska ravnica — caiion de la riviere Cijevna MALM INFfiRIEUR (OXFORDIEN) Fig. 1 Calcaire grumeleux a Codiacees (X 17,5). PI. mince 1198-57. Dans Tassociation: Thaumatoporella parvovesiculifera (Rain.) et Foraminiferes peu a bon dan ts Bordure nor d de la Zetska ravnica — canon de la riviere Cijevna MALM INFfiRIEUR Fig. 2 Calcaire grumeleux k Oodiacčss (X 17,5). PL mince 1199-57. Dans l'association: Protopeneroplis striata Weynschank Bordure nord de la Zetska ravnica — canon de la riviere Cijevna MALM INFfiRIEUR Fig. 1 Calcaire peu bitumineux a Cladocoropsis mirabilis Felix (X 16). Pl. mince 1152-57. Dans l'association: Thaumatoporella parvovesiculifera (Rain.), Cyano-phytes, Coddacees; puis Kurnubies et autres Faraminifšres Bordure nord de la Zetska ravnica—Spil j a MALM INFERIEUR (probablement KIMMfiRIDGIEN INFfiRIEUR) Fig. 2 Calcaire grumeleux a Pseudocyclammina sp. (X 35). Pl. mince 1124 a-57. Dans l'association: rares «I.ituo7iella» et autres Foraminiferes, rare Clypeina jurassica Favre Bordure nord de la Zetska ravnica—Spilja malm superieur (kimmeridgien superieur) lis Fig. 1 et 2 Calcaire peu bitumineux a Microproblematica, Thaumatoporella parvovesiculi-fera (Rain.), «Macroporella» sellii Crescenti, Kurnubia palastiniensis Henson, etc. (fig. 1 — X 30, fig. 2 — X 70). PL mince 1071-57 Bordure nord de la Zet&ka ravnica — environs de Spilja MALM SUPERIEUR (KIMMERIDGIEN SUPERIEUR) Fig. 1 Calcaire peu bitumineux a Cyanophytes (X 30). PI. mince 833-57 Bordure nord de la Zetska ravnica, Dečič MALM SUPfjRIEUR (KIMMERIDGIEN SUPERIEUR) Fig. 2 Calcaire peu bitumineux a Cyanophytes et 'rganogčne-dštritique, subcristallin, k Clypeina (?) sp. (X 28). PI. mince 344-61. Dans l'assotiattan: Foraminif&res, Microproblematica, Micro-gas t^ropodes Herzegovine du sud, Uskoplje-Orah MALM (couches d Cladocoropsis mtrabWis) Fig. 2 Calcaire a «Ma.CToporella» sellii Crescenti, Thaumatoporella parvovesiciilifera (Rain.) etc. (X 28). PL mince 354-61. Dans Tassociation: Kurnubies, Lituolides, Labyrinthina Herzegovine du sud, XJskoplje-Orah MALM (couches h Cladocoropsis mirabilis) Fig. 1 et 2 Calcaire h Bullopora sp., Kurnubies, autres Foraminif&res et Dasycladacees (fig. X — X 50, fig. 2 — X 28). Pl. minces 566 et 567-61 Herz eg ovine du sud, C ovine-Vlaka MALM (couches k Cladocoropsia mirabilis) Fig. 1 Calcaire a Foraminifšres (X 28). PL mince 346-61. Dans l'association: rares Kumubia et Thaumatoporella Herzčgovine du sud, Uskoplje-Orah MALM (KIMMfiRIDGlEN) Fig. 2 Calcaire a Cyanophytes (X 15). Pl. mince 348-61. Dans l'association: rares Ostracodes et Foraminiffcres Herzčgovine du sud, Uskoplje-Orah MALM SUPERIEUR (couches & Clypeina jurassica) Fig. 1 Calcaire š Kurnubia palastiniensis Henson et Pfenderina sp. (X 28). PI. mince 512-61. Dans l'association: Thaumatoporella parvovesiculifera (Rain.) Herzegovine du sud, environs de Radovan ždrijelo MALM SUPEHIEUR Fig. 2 Calcaire a Charophytes (X 28). PI. mince 444-G1 Herzegovine du sud, Ščenica MALM SUPI5R1EUR (couches a clypelna jurassica) Fig. 1 Calcaire marneux a Ostracodes (X 28). Pl. mince 360-61 Herzčgovine du sud, au sud d'Orah MALM SUPFRIEUR (PORTLANDIEN, couches k Clypeina jurassica) Fig. 2 Calcaire dolomitique k Clypeina jurassica Favre (X 28). Pl. mince 349-61 Hercegovine du sud, au sud d'Orah MALM SUPERIEUR (PORTLANDIEN) Fig. 1 Calcaire organogene a Clypeina jurassica Favre, Pianella gigantea (Carozzi), Tintinnines aberrantes et Foraminiferes peu abondants (X 28). PI. mince 521-61 Herzčgovine du sud, Radovan ždirijelo INFRAVALANGINIEN Fig. 1 Calcaire a Coprolithes — Favreina salevensis (Parejas) (X 35). PI. mince 362-61 Herzegovine du sud, Zaplanik INFRAVALANGINIEN (couches k Clypelna jurassica et Tintinnines aberrantes) LA SČRIE JURASSIQUE DE LA REGION MOSOR—BIOKOVO—BAClNE (Tableau Ne 8) Planches: CX a CXXI 1? — Geologija St. 0 Fig. 1 Calcaire a Palaeodasycladus mediterraneus Pia (X 18). PI. mince 1000-61. Dans l'association: Thaumatoporella parvovesicultfera (Rain.) et Foraminiferes peu nombreux Montagne Biokovo, versants suds LIAS (partie inoyenne de la sčrie liasique) Fig. 2 Calcaire k Thaumatoporella parvovesiculifera (Rain.), (X 27,5). PI. mince 1001-61 Montagne Biokovo, versants suds LIAS (partie moyenne de la serie liasique) Fig. 1 et 2 Calcaire š Orbitopsella s p., Clomospira sp., Lituolidčs, Trocholines et debris divers peu abondants (fig. 1 — X 27, fig. 2 — X 60). PI. mince 1061-61. Dans l'association: rares Codiacees Montagne Biokovo, versants suds LIAS (partie moyenne de la sčrie liasique) Fig. 1 et 2 Calcaire oolithique-detritique k Dictyoconus cayeucci (Lucas), Endothyra, etc. (X 37). PI. mince 1005 a-61 Montague Biokovo, versants suds DOGGER INFERIEUR Fig. 1 et 2 Calcaire oolithique-detritique a Dictyoconus cayeuxi (Lucas), (X 37). PI. mince 1005 a-61 Montagne Biokovo, versants suds DOGGER INFERIEUR Fig. 1 Calcaire oolithique-detritique a Protopeneroplis striata Wevnschenk (X 65). PI. mdnce 1012-61 Biiokovo de l'ouest, environs de Zadvarje DOGGER SUPfiRIEUR Fig. 2 Calcaire oolithique-detritique a Trocholines (X 65). PI. mince 1013-61. Dans Tassociation: Protopeneroplis striata Weynschenk, petits Foraminiferes, debris de Molilusques, d'Echiinodermes et de Dasycladacees Biokovo de l'ouest, environs de Zadvarje DOGGER SUPERIEUR Fig. 1 et 2 Calcaire organogene-detritique, subcristallin, a Selliporella donzellii Sartoni & Crescenti et debris de Mollusques (X 17,5). PI. mince 994-61 Montagne Biokovo, versants suds du St Ilija DOGGER SUrEFIEUR Fig. 1 Calcaire grumeleux a Pfenderines, autres Foraminiferes et debris divers peu abomdan ts (X 27,5). PL mince 1071-61 Biokovo de l'ouest, Kolibret-Cikeš MALM INFERIEUR (couches Les plus an&ennes) Fig. 2 Calcaiire legerement marneux a Pseudocyclammina lituus (Yocoyama), (X 27,5). Pl. mince 1123-61. Dans 1'association: Thaumatoporella parvovesiculifera (Rain.), Cladocoropsis mirabilis Felix et Kurnubia Montagne Biokovo, Babinjača MALM (OXFORDIEN-KIMMERIDGIEN) Fig. 1 et 2 Calcaire a Labyrinthina mirabilis Weynschenk (X 27,5). PI. mince 703-60. Dans 1'association: ConicospiriUina, Pseudocyclammina et autres Foraminif&res Montagne Mosor, sud-ouest de Ljubljen MALM (KIMMERIDGIEN) Fig. 1 et 2 Calcaire grumeleux & Cly petna jurassica Favre, Pianella cf. gigante a Carozzi et Foraminiferes peu nombreux (X 27,5). PI. mince 1126-60 Montagne Mosor, Ljubljen de l'ouest MALM SUPČRIEUR (PORTLANDIEN) Fig. 1 Calcaire gfumeleux, en partie oolithique, k Clypeina jurassica Favre et Co-diacčes (X 27,5). PI. mince 713-60 Montagne Mosor, versant sud-est MALM SUPfcRIEUR (PORTLANDIEN) Fig. 2 Calcaire cristaJlin a Clypeina jurassica Favre et Tintinnines aberrantes — Campbelliella mileši Radoičič et aut. (X 17,5). PI. mince 2297-60 Environs du lac Bačinsko jezero INFRA VALANGINIEN Fig. 1 Calcaire grunieleux a Tintinnines aberrantes — Campbelliella mileši Radoičič (X 40). PL mince 1074-61. Dans 1'association: Salpingoporella annulata Carozzi et petits Foraminiferes peu nombreux Biokovo de l'ouest, Kolibret-Cikeš VALANGINIEN Fig. 1 et 2 Calcaire, en partie oolithique jusqu'a grumeleux, a Favreina salevensis (Parejas), Codiacees, Microgastčropodes, etc. (X 50). PL mince 2298-60 Environs du lac Bačinsko jezero VALANGINIEN LA SBRIE JURASSIQUE DE LEMES ET DE SES ENVIRONS (Tableau Jfc 9) Planches: CXXII ži CXXXIII Fig. 1 et 2 Calcaire a Orbitopsella praecursor (Gumbel), (X 17,5). PI. mince 2420-60. Dans l'association: Glomospira sp. et autres Foraminiferes Lemeš, environs de Vinica LIAS Fig. 1 et 2 Calcaire k Ostracodes et Faraminiferes peu abondants (fig. 1 — X 20; fig. 2 — X 27,5). PI. mince 2423-60 Lemeš, environs de Vinica LIAS (couches £ Lithiotis) Fig.1 et 2 Calcairo & Foraminiferes (Lituolidčs, Glomospira et autres), debris de Mollus-ques etc. (fig. 1 — X 30; fig. 2 — X 72). PI. mince 2412. Dans l'association: Palaeodasycladus mediterraneus Pia. Lemeš, environs de Vinica LIAS (couches ž LftAiotis) Fig. 1 et 2 Calcaire a Gloviospira sp., Trochamminides, Verneuilinides, autres Foramini-feres et Thaumatoporella parvovesiculifera (Rain.) Lemeš, environs de Vinica lias moyen-sup2rieur Fig. 1 Caicaire oolithique a rares debris organogene (X 27,5). PI. mince 2416-60 Lemeš, environs de Vinica LIAS MOYEN-SUPE11IEUR Fig. 2 Caicaire micro-oolithique k Clomospira sp., etc. (X 27,5). PI. mince 2417-60 Lemeš, environs de Vinica LIAS MOYEN-SUPfiRIEUR Fig. 1 et 2 Calcaire a Pfenderines (X 72). PI. mince 2400-60. Dans l'association: Thauma-toporella parvovesiculijera (Rain.) L-emeš, environs de Kuk DOGGER SUP£RIEUR-MALM INFŽRIEUR Fig. 1 Calcaire & Thaumatoporella parvovesiculifera (Rain.) et Foraminiferes (Pfen- derines et autres), (x 72). PI. mince 2402-60 Lemeš, environs de Kuk DOGGER SUP£RIEUR-MALM INFERIEUR Fig. 2 Calcaire subcristallin a rares Foraminiferes (Miliolides et autres) etc. (X 75). PI. mince 2338-60 Lemeš DOGGER SUPER IE UR (?)—MALM INFfiRIEUR Fig. 1 Caicaire a Radiolaires (X 80). PI. mince 2340-60 Lemeš MALM INFLRIEUR Fig. 2 Caicaire a Globigerines peu abondantes (X 100). PI. mince 2341-60. Dans l'asso- ciation: Radiolaires et Lamellibranches pelagiques Lemeš MALM INFF.R1EUR Fig.1 et 2 Calcaire a Saccocoma Agassiz (X 28). PI. mince 2344-60 Lemeš MALM (KIMMCRIDGIEN — calcaire k nombreux Ammonites) Fig. 1 Caicaire a Saccocoma Agassiz (X 28). PI. mince 2346-60. Dans l'association: Globochaete alpina Lombard. Lemeš MALM (KIMMERIDGIENj Fig. 2 Caicaire a Radiolaires (X 28). PI. mince 2350-60 Lemeš MALM (KIMMERIDGIEN) planche cxxxii Fig. 1 Calcaire a Conicospirillina cf. basiliensis Mohler (X 72). PL mince 2365-60 Lemeš, au nord d'Orlovaca MALM SUPERIEUR (PORTLA NDIEN) Fig. 2 Calcaire a Aptychus, petits Cyanophytes etc. (X 17). Pl. mince 2367-60 Environs de LemeŠ, au nord d'Orlovafia MALM SUPERIEUR (PORTLANDIEN) Fig. 1 Calcaire organogene-detritique k Codiacčes (X 27,5). PI. mince 2368-60. Dans Tassociataon: Teutloporella cf. obsoleta Carozzi Environs de Lemeš, au nord d'Orlovača MALM SUPERIEUR (PORTLAND EEN) Fig. 2 Calcaire k SalpinQoporella annulate Carozzi (X 27). PI. mince 2375-60. Dans 1'association: Foraminiferes peu abondants Environs de Lemeš, Orlovača Ntf.OCOMIEN LA S£RIE JURASSIQUE DES ENVIRONS DE ROVINJ (Tableau 10) Planches: CXXXIV k CXLI Fig. 1 Caicaire k Pfenderinides (X 27,5). PI. mince 1837-60. Dans l'association: petits Foraminiferes peu abondants et Thaumatoporella parvovesiculifera (Rain.) Environs de Rovinj, St Eufimija-Križ-Figarola MALM INFERIEUR (ou DOGGER-MALM) Fig. 2 Caicaire k Pfenderinides et autres rares Foraminiferes (X 70). PI. mince 1840-60 Environs de Rovinj, S* Eufimija-Križ-Figarola MALM INFERIEUR (ou DOGGER-MALM) Fig. 1 et 2 Calcaire organog&ie š Bačinella irregularis Rad. et nombreuses Trocholines (X 30). PL mince 1865-60. Dans l'association: aiufcres rares Foraminiferes et Thaumatoporella parvovesiculifera (Rain.) Environs de Rovinj, Figarola MALM SUPER 1EUR (KIMM£KIDGIEN, probablement SUPfiRiEUR) Fig. 1 Caicaire a Trocholines et autres Foraminiferes (X 30). PI. mince 1866-60 Rovinj, Figarola MALM SUPERIEUR (probablement KIMMERIDGIEN SUPfiRIEUR) Fig. 2 Caicaire a Aeolisaccus sp., Ostracodes et Foraminiferes peu nombreux (X 30). PI. mince 1873-60 Rovinj MALM SUPERIEUR (PORTLANDIEN) Fig. 1 Calcaire organogene a Thaumatoporella parvovesiculifera (Rain.) et nombreux Foraminiferes (Pseudocyclammina, Textularictes, Verneuilinides et Endothyra ?), (X 30). PI. mince 1004-60 Rovinj, Zlatni rt MALM SUPERIEUR (PORTLANDIEN) Fig. 2 Calcadre a Favreina salevensis Parčjas (X 30). PI. mince 1906-60 Rovinj, Zlatni rt MALM SUPfiRIEUR (PORTLANDIEN) Fig. 1 et 2 Calcaire criptocristallin et grumeleux k Clypeina jurassica Favre (X 30). PL minces 1884 et 1885-60. Dans l'association: Ostra codes et Foraminiferes peu abondants Rovinj malm supfirieur (portlandien) Fig. 1 et 2 Calcaire finement detritique a Foraminiferes (Pseudocyclammina, Endothyra ? et autres), (fig. 1 — X 15, fig. 2 — X 30). PL minces 1908 et 1908 a-60. Dans l'association: rares Trocholines et Bačinella irregularis Rad. Hovinj, Zlatni rt MALM SUPEHIEUR (PORTLANDIEN) Fig. 1 Calcaire crip toe ristallin a Calpionelles fort rares (X 200). PI. mince 1875-60 Rovinj MALM SUPfiRIEUR (PORTLANDIEN) Fig. 2 Calcaire a Tintinnines aberrantes: Campbelliella mileši Rad. et Tintinnopsella sp. (X 20). PI. mince 1924-60 Rovinj, Zlatni rt VALANGINIEN Fig. 1 et 2 Calcaire a Salpingoporella annulate, Cairoezi (X. 30). PI. mince 1920-60 Rovinj, Zlatni rt VALANGINIEN LA SERIE JURASSIQUE DES ENVIRONS DE SOŠICE (ZUMBERAK) (Tableau Ke 11) Planches: CXLII—CXLVIII Fig. 1 Calcaire oolithique, azoique (X 27). PI. mince 96-61 Zumberak, environs de Sošice LIAS INFERIEUR Fig. 2 Calcaire organogene-detritique — debris de Dasycladacees, d'Echinodermes et de Mollusques; Microgasteropodes (X 27). PI. mince 98-61 Zumberak, environs de Sošice HAS INFfiRIEUR Fig. 1 et 2 Calcaire organogene, subcristallin, a Palaeodasycladus mediterraneus Pia, rares Foraminifdres et debris de Mollusques (X 15). PI. mince* 119 et 120-61 2umberak, environs de Pogana jama LIAS INFfiRTEUR-MOYEN Fig. 1 Calcaire oolithique & petits Foraminiferes peu nombreux et fin debris divers (X 27). PI. mince 99-61 Žumberak, environs de Sošice LIAS MOYEN Fig. 2 Calcaire microgrumeleux a Lituosepta recoarensis Cati (X 27). PI. mince 102-61. Dans l'assiociaition: tres rares petits Fiaraminiferes et Thaumatoporelles trans-formees Zumberak, environs de Sošice LIAS MOYEN Fig. 1 Calcaire microgrumeleux a Lituosepta recoarensis Cati, petits Foraminiferes peu nombreux et Thaumatoporelles transformees (X 30). PI. mince 102-61 Zumberak, environs de Sošice LIAS MOYEN-SUPEK1EUR Fig. 2 Calcaire organogene-detritique & SpiriUina liassica (Jones) et debris d'Echino-dermes (X 40). PI. mince 78-61. Dans 1'assocdation: Vidalina martana Farinacci et Lag6nides Zumberak, environs de Sošice LIAS SUPERIEUR Fig. 1 Calcaire organogdne-detritique a Cristellaria et autres Lagenides et debris abondants d'Echinodermes et de Mollusques (X 30). PI. mince 105-61. Dans l'association: Spirillina liassica (Jones), Vidalina martana Farinacci et Ophtal-midiidčs Žumberak, environs de Sošice LIAS SUPER1EUR Fig. 2 Calcaire organ ogene-detritique — debris d'Echinodermes et de Mollusques (fragments de Saccocoma), (X 30). PI. mince 108-61. Dans l'association: Vidalina, Spirillina etc. Zumberak, environs de Sošice LIAS SUPfiRlEUR ou LIAS-DOGGER Fig. 1 Calcaire organogene-detritique a Petrascula bursiformis Ettalon (X 30). PI. mince 91-61. Dans l'association: Bačinella irregularis Radoičič et Codiacčes apparentčes Zumberak, environs plus large de Sošice MALM INFfiRIEUR Fig. 2 Calcaire k rares Radiolaires calcifies et Lamellibranches pelagiques (X 43). PI. mir.ce 109-61 Zumberak, environs de Sošice MALM SUPEREEUR (KIMMERID GIEN-PORTLANDIEN) Fig. 1 Calcadre a Calpionella alpina Lorenz et Calpionella elliptica Cadisch (X 100). PL mince 110-61 Zumberak, SoSice MALM SUPERTEUPv (PORTLANDIEN) Fig. 2 Calcadre a Calpionella alpina Lorenz et Calpionella elliptica Cadisch (X 43). Pl. mince 111-61. Dans l'association: Clobochaete alpina Lombard, spicules de Spongiaires, puis rares Oph tal mid i ides et autres Foramirtiferes Zumberak, Sošice MALM SUPERIELiR (FORTLANDIEN) LES AUTRES MICROFAClES JURASSIQCES Planches: CXLIX a CLXV Fig. 1 et 2 Calcaire š Annelides, Microgasteropodes et petits Foraminiferes peu abondants (X 30). PI. mince 906-63 Environs d'Osjecenica, pres de Grahovo; Montenegro LIAS INFERIEUR (couches les plus anciennes) Fig. 1 et 2 Calcaire pseudo-oolithique k Pelleria bonomii* (Vialli) Grubič (fig. 1, nčgatif — X 7,5; fig. 2, detail — X 17,5). PI. mince 1397-64. Dans 1'association: autres Hydrozoaires, debris d'Echinodermes et petits Foraminifžres; Vidalina martana Fairinacci, Spirillina liassica (Jones) et autres. (= pl. CLI) Montagne Lovčen, Bukovica LIAS INFERIEUR * Determination: A. GRUBlC Fig. 1 et 2 Calcaire pseudooodithique a Hydrozoaires (fig. 1, negatif — X 7,5; fig. 2, detail — X 3 7,5). PI. mince 1396-64. Dans I'association: Pelleria bonomii (Vialli) Grubič, debris d'Echinodeinmes et petits Fonaminiferes: Vidalina martana Farinacci, Spirillina Imssica (Jones) et autres Montagne Lovčen, Bukovica LIAS INTERIEUR Fig. 1 Calcaire oolithlque k debris divers peu abondant (X 35). PI. mince 556-62 Environs de Blizna dans la vallee de Marača, Montenegro LIAS INFfiRIEUR (couches les plus anciennes) Fig. 2 Calcaire a Lituosepta recoarensis Cati (X 17,5). PL mince 529-62 Martiničkio Gostije, Javcxrak; Montčnčgro LIAS Fig. 1 Calcaire a debris d'Echinodermes (X 17). PI. mince 248-57 Environs plus large de Kopilje, pres de Seoca, Montenegro LIAS (partie moyenne de la sene liasique) Fig. 2 Calcaire oolithique a debris d'Echinodermes (X 17). PL mince 250-57 Environs plus large de Kopilje, pres de Seoca, Montenegro LIAS (parlie moyenne de la serie liasique) Fig. 1 et 2 Calcaire oolithioue & Echinodermes, pris de la dolomitisation (X 33). PI. mince 67-63 Environs plus large de Nikšič, prčs de Bročanac, Montenegro LIAS (MOYEN-SUPHfllEUR) Fig. 1 et 2 Calcaire organ o gene, crisfallin, a Spirillina liassica (Jones), Lagenides, debris d'Echinodermes et Mollusques (X 35). PI. mince 1875-64. Dans l'association: petits Ammonites, Trocliolines et rares Vidalines (= pl. CLVI) Boka Kotorska, Vrmac LIAS S17PERIEWR Pig. 1 et 2 Calcaire organogfcne, cristallin, k Lagenidčs, Trocholines et debris d'Echinodermes et de Mollusques (X 35). PI. mince 1876-64. Dans l'association: petits Ammonites Spirillina liassica (Jones) et rares Vidalines (= pi. CLV) Boka Kotorska, Vrmac LIAS SUPfiRIEUR Fig. 1 Calcaire organogene š Teutloporella gallaeformis Radoičič (x 17,5). PI. mince 1685-64 Domaine entre Grab et Konavli, environs de Veliki Oro DOGGER SUPfiRIEUR Fig. 1 Calcaire organogene-detritique a Codiacees C1 (X 75). Pi. mince 554-62. Dans l'association: Conicospirillina basiliensis Mohler Sujaci — dans la vallde de Morača, Montčnčgro MALM INFEKIEUK Fig. 2 Calcsire organogene a Bačinella irregularis Radoičič (X 27). PI. mince 01803 Au nord de Nikšič, vers Vojnik, Gvozd MALM INFfcRIEUR Fig. 1 et 2 Calcaire organogene-detritique, subcristallin, a Microproblematica Pr6 (X 50). PI. mince 01707. Dans 1'association: Codiacees, Hydrozoaires, etc. Domaine de la montagne Burmitoir, KI ješ tine MALM INFffRIEUR Fig. 1 Calcaire d Sphaeractinidčs (X 17). PI. mince 01720. Dans l'association: Aeoli-saccus sp. Montagne Durmitor MALM (KIMMERIDGIEN) Fig. 2 Calcaire h Pianella grudii Radoičič et Ostracodes (X 45). PL mince 1889-63 Environs de Miloviči, Banjami; Montenegro MALM SUPERIEUR (KIMMERIDGIEN SUPERIEUR-PORTLANDIEN) r Fig. 1 et 2 Calcadre peu bitumineux a Aeolisaccus sp., Ostraoodes, petits Foraminiferes peu nombreux et debris de Dasycladacees (fig. 1 — X 95, fig. 2 — X 17). PI. minces 248 et 246-62 Biočki stan, environs de Nikšička Zupa MALM SUPfiRIEUR (KIMMERIDGIEN SUPfiRIEUR-PORTLANDIEN) Fig. 1 et 2 Calcaire organogene-detritique a Nipponophycus cf. ramosus Yabe & Toy a ma, (X 27,5). PI. mince 1280-63 Domadne de la montagne Orjen, Ubli MALM SUPERIEUR (FORTLANDIEN) Fig. 1 Calcaire a Dasycladacees recristallisčes — 1© plus vraisernblablement il est question de l'espece Pianella gigantea Carozzi (X 27,5). PI. mince 1278-63 Domaine de la montagne Orjen, Ubli MALM STj PERI EUR Fig. 2 Calcaire organogene-detritique a Dasycladacees et Codiacees (X 27,5). PI. mince 1274-63 Domaine de la montagne Or jen, Ubli MALM SUPER1EUR Fig. 1 Calcaire a Spirillina sp. ©t Radiolaires (X 90). PI. mince 3148-60 Hercegovine du nord, Tjentište-Suha MALM SUFfiRIEUR (PORTLANDIEN — couches a Calpionelles) Fig. 2 Calcaire a debris de Lamellibranches pelagiques et Globochaete alpina Lombard (X 95). PI. mince 3151-60 Herzegovine du nord, Tjentište-Suha malm supfiRlEUR (PORTLANDIEN — couches h Calpionelles) Fig. 1 et 2 Calcaire organog^ne i Trocholines, Pseudocyclammina, Protopeneroplis ?, DasycladacSes (Macroporelles, Aciculairia ert autres), Codiacees, Micmogast4ro-podies, ©te. (X 18,5). PI. mince 1990-62 Boka Kotorska, Ljuta MALM SUPfiRIEUR? JURSKI SF.DIMENTI MED ZAGRADCEM IN RANDOLOM V DOLINI KRKE Ljudmila Sribar S 7 slikami v prilogi Uvod Leta 1961 smo na Dolenjskem kartirali območje lista Ribnica 52/3. Geološko skupino je vodila Lija Ri j avec, sodeloval pa je poleg mene še Zvonko Mencej. Med študijem literature za pripravo terenskega dela smo dobili uporaben podatek pri Germovšku (1950), ki omenja pri izviru Globočca, jugozahodno od Zagradca, najdbe litiotid in drugih školjk ter koral v srednjeliadnem apnencu. Kartiranje smo pričeli pri Zagradcu in ugotovili, da so od tu do Randola nad Krko razviti vsi sedimenti jure od liade do malma. Pri Zagradcu in Randolu so jurske plasti ločene od ostalih s prelomoma, ki potekata od jugozahoda proti severovzhodu. Na tem območju smo našli tudi številne vodilne jurske fosile, zlasti mikrofosile, ki so nam v glavnem omogočili stratigrafsko razčlenitev skladov, delno pa smo plasti horizon-tirali po njihovi medsebojni legi. Biostratigrafski opis Po fosilnih in mikrofosilnih ostankih ter stratigrafski legi smo jurske plasti med Zagradcem in Randolom razdelili takole: spodnja liada, srednja liada, zgornja liada in dogger, spodnji malm in zgornji malm. Spodnja liada Spodnjeliadne plasti leže na zgornjetriadnem dolomitu noriške in retske stopnje. Te plasti vsebujejo ostanke alg Sphaerocodium bomemanni Rothpl. in megalodontide. Glavni dolomit je v glavnem razvit v dolini Krke; najjužneje sega na pobočje Šiškega vrha (516 m). Za zgornji del glavnega dolomita v bližini postopnega prehoda triada—jura je zelo značilna pasovitost, ki smo jo opazovali tudi pod mikroskopom. V kamenini se menjavajo temnejši in svetlejši različno široki pasovi, kar je posledica različne zrnavosti dolomita ter primesi drobnega organskega detritusa in gline. Mikrokristalni pasovi s primesjo gline in drobnega organskega detrilusa so temnejši, svetlejši pasovi pa so sestavljeni iz drobnozrnatega dolomita. Pasovit dolomit postopno prehaja v dolomiti-ziran apnenec. Više postaja apnenec vedno- bolj čist in kompakten ter je pogosto preprežen s kalcitnimi žilicami. Vsebuje ostanke brahiopodnih in gastropodnih lupinic in je pogosto marogast, ponekod pa kaže oolitno strukturo. Med Zagradcem in Randolom smo mejo med triado in juro potegnili tam, kjer zgornjetriadni glavni dolomit postopno preide v siv gost apnenec, oolitni apnenec in apnenec z lupinicami brahiopodov in gastro-podov. V manjši količini dobimo tudi temno siv zrnat dolomit. Spodnjeliadnih plasti na opisanem območju nismo mogli dokazati s fosili, na njihovo starost sklepamo le po legi med zgornjetriadnim glavnim dolomitom in srednjeliadnimi skladi z litiotidami. Severozahodno od Šiškega vrha smo v spodnjeliadnem apnencu našli algo Palaeodasycla-dus mediterraneus (Pia) (1. si.), ki je pa ne moremo imeti za vodilni fosil spodnje liade. V profilu jurskih skladov na Mali gori smo našli to algo v srednji Kadi v ho-rizontu z litiotidami in s foraminifero OrbitopseUa praecursor (Šribar, 1965). Tudi v vzorcih apnenca, ki jih je Grad nabral pri kartiranju v kamnolomu pri Podutiku, smo našli ostanke alge Palaeodasycladus mediterraneus. Vendar liadnih plasti na območju Podutika nismo mogli podrobno horizontirati, ker litiotidni horizont ni izrazit. Mejo med triado in juro pa smo tu potegnili med plastmi z me-galodontidami in sivim apnencem, ki ponekod vsebuje oolite. Po Farinaccijevi in Rado-ičičevi (1964) je alga Palaeodasycladus mediterraneus razširjena v zgornjem delu spodnje liade, v srednji liadi in delno v zgornji liadi. Njena razmejitev navzgor in navzdol ni jasno označena. Po Sartoniju in Crescentiju (1962) pa nastopa tudi v plasteh retske stopnje. Enak podatek smo našli tudi v mikrnpaleontološkem atlasu Agip Mineraria, 1959. Srednja liada Tudi srednja liada je na območju med Zagradcem in Randolom razvita apneno. Apnenec je temno siv in vsebuje lepo vidne bele lupine litiotid. Horizont z litiotidami smo sledili neprekinjeno od izvira Glo-bočca pri Zagradcu, kjer jih je omenil že Germovšek (1950), do Randola pri Krki. Horizont z litiotidami vsebuje tudi vodilno srednje-liadno foraminifero Orbitopsella praecursor (Gumb.), ki smo jo našli v ooldtnem apnencu (2. f?l.). Plasti z litiotidami so debele prek 50 m. Zgornja liada-dogger V sedimentih med srednjeliadnimi plastmi, dokazanimi s fosili, in spodnjemalmskimi skladi z vodilno mikrofloro, nismo našli fosilnih ostankov. Po legi smo te vmesne sedimente prišteli zgornji liadi in doggerju. Med njimi nismo nikjer zasledili diskordance. Sestavljajo jih v glavnem oolitni apnenec z različno velikimi ooliti, nadalje siv gost apnenec in marogast apnenec. V tem delu jure nismo dobili mikrofosilov, ki bi imeli večji pomen za določitev starosti plasti. Našli smo sicer nekatere foraminifere, med njimi za dogger najbolj značilne primerke iz družine Valvulinidae in Textulariidae (3. si.), vendar vrst nismo mogli določiti. Te foraminifere nastopajo često v vzorcih iz srednjega dela jure. Dobili smo jih tudi pri mikropaleontološki obdelavi jurskega profila na Mali gori (S r i b a r , 1965). Spodnji malm Malm smo s pomočjo- mikrofosilnih ostankov razdelili v spodnji malm (oxfordij-spodnji kimmeridgij) in zgornji malm (zgornji kimme-ridgij-portlandij). Spodnji malm (oxfordij-spodnji kimmeridgij). Plasti spodnjega malma ležijo konkordantno na doggerskih skladih. Sestavljata jih svetlo do temno siv gost apnenec in oolitni apnenec. Njihova starost je dokazana s fosili. Najpomembnejši so spodnjemalmski hidrozoji. Spodnjemalmski oolitni apnenec vsebuje ostanek foraminifere ,Protope7ieroplis striata Weynschenk (4a in 4b si.), ki je vodilna za zgornji del doggerja in spodnji malm. Kaže, da je ta foraminifera pri nas redka, kajti kljub velikemu številu pregledanih vzorcev iz jurskih sedimentov je bila ta najdba dolgo osamljena. šele pozneje, pri kartiranju lista Ilirska Bistrica 65 in Kranj 65, sme v spodnjemalmskih plasteh ponovno našli foraminifero Protopeneroplis striata Weynschenk. Po literaturnih podatkih (Weynschenk, 1950) nastopa ta foraminifera v zgornjem doggerju in spodnjem malmu. V naših najdiščih pa smo jo vedno našli le v spodnje-malmskem apnencu. Med Zagradcem in Randolom so v spodnjem malmu zelo pogostne alge iz rodu Coscinoconus sp. (5. si.). Te alge so številne tudi v drugih območjih Slovenije v spodnjemalmskih plasteh. Zgornji malm (zgornji kimmeridgij-portlandij) Zgorajemalmske plasti leže konkordantno na spodnjemalmskih. Sestavlja jih povečini svetlo siv apnenec, ki kaže ponekod oolitno ali psevdooolitno strukturo. Apnenec se menjava s svetlim zrnatim dolomitom. Med Zagradcem in Randolom smo našli v številnih vzorcih zgor-njemalmskega apnenca vodilno algo Clypeina jurassica F a vre (6. si.). V zgornjem delu zgornjega malma nastopajo skupno s klipeinami tudi velike tintinine = Bankia striata (Carozzi). Na zgornjemalmskih plasteh leži spodnjekredni apnenec. Tudi starost tega apnenca smo dokazali z mikrofosili. JURASSIC SEDIMENTS BETWEEN THE VILLAGES ZAGRADEC AND RANDOL IN KRKA VALLEY In the course of geological mapping on the sheet Ribnica 52/3 between the villages Zagradec and Randol fairly complete stratigraphic section of Jurassic sediments ranging from Liassic to Malm has been encountered. In this region some Jurassic guide fossils and microfossils have been found. This first and the stratigraphical position of the strata enabled the division of Jurassic sediments into Lower and Middle Liassic, Upper Liassic-Dogger, Lower Malm and Upper Malm. Lower Liassic. The Lower Liassic strata are conformably underlain by the Upper Triassic dolomit of the Noric and Rhaetic stage. The Triassic dolomite grades into dolomitized limestone and gray limestone containing localy oolites and relics of brachiopods and gastropods. In the described region the Lower Liassic strata couldn't be identified by means of the fossils; conjectures about their age hawe been possible only on the basis of their position between the Upper Triassic dolomite and Middle Liassic strata with lithiotides. In the north western part of the "Šiški vrh" Palaeodasycladus mediterranues (Pia) (Fig. 1) has been fund. This alga is widespread from the upper part of Lower Liassic to the lower part of the Upper Liassic but is not considered to be the guide fossil of the Lower Liassic. Middle Liassic. The Middle Liassic limestone is predominantly dark gray in colour and contains relics of white shells of lithiotides. The horizon with lithiotides has been traced without interruption from Globočec near Zagradec, where it has been already mentioned by Germovšek (1950) to Randol near the Krka river. In the strata with lithiotides the guide Middle Liassic foraminifer Orbitopsella praecursor (Giimbel), (Fig. 2) has been identified. Upper Liassic-Dogger. In the sediments occurring between the Middle Liassic strata proved by the presence of fossils, and the Lower Malmian strata containing the guide microflora, there were no determinable fossils, by which the age of these interbedded strata could be identified. These sediments have been ranged in the Upper Liassic and Dogger only owing to their position. They are composed of oolitic limestone, gray and dense limestone and mottled limestone. In general some small foraminifers belonging to the family of Valvulinidae and Textulariidae. (Fig. 3) have been found in this part of the Jurassic. Lower Malm (Oxfordien-Lower Kimmeridgien) The age of the Lower Malmian strata conformably overlying the Doggerian beds is established by the presence of the hydrozoan fauna The foraminifer Protopeneroplis striata Weynschenk (Figs 4 a and 4 b), which is the guide fossil for the upper part of Dogger and for the Lower Malm, has been identified in the Lower Malmiian oolitic limestone. In the Lower Malmian limestone between Zagradec and Randol the algal remnants of Coscinoconus (Fig. 5) are very abundant. Upper Malm (Upper Kimmeridgien-Portlandien). The Upper Malmian strata overlying conformably the Lower Malmian strata are mostly represented by light gray limestone of oolitic and pseudoodlitic texture. The limestone alternates with granular dolomite. Here the guide fossil is Clypeina jurassica Favre (Fig. 6), occurring in the upper part of the Upper Malm together with Tintinnides aberrantes — Bankia striata (Ca-rozzi). The Upper Malmian strata are overlain by Lower Cretaceous limestone. LITERATURA Agip Mineraria, 1959, Microfacies italiane (dal Carbonifero al Miocene medio). 35 pp., T-CXLV tt., S. Donato Milanese. E 1 i s , B. et Messina, A. R., 1940, Catalogue of Foraminifera. Special Publ. Am. Mus. of Nat. Hist. New York. Farinacci, A., 1963, L'«Orgamismo C» Favre 1927 appairtdene alle Teredinidae? Geologi ca Romana, vol. II., Roma, Farinacci, A., 1964, Sulla posiziane systematica e stratigrafica di Protopeneroplis striata Weynschenk, 1950. Geologi ca Riomana, vol. Ill, Roma. Farinacci, A. & Radoičič, R., 1964, Correlazione fra serie giuresi e cretacee dell"Appennino centrale e delle Dinaridi Esterne. La ricerca scienti-fica,. anno 34, serie 2, II-A. Roma. Germovšek, C., 1950, Hidrogeološki pregled Krke in njenih pritokov od izvira do izliva Radulje. Arhiv Geološkega zavoda v Ljubljani. Nikler, L., Sokač, B. et Ivanovič, A., 1964, Die Gesellschaften der Mikrofossilien der Jura und Rreide des s iidost Lichen Velebit. Buli. Sci., Cons. Acad. RSF Yougosl., T. 9, No. 3, Zagreb. K e r č m a r, D., 1962. Prve najdbe zgornjejurskih apnenih alg v Sloveniji. Geologija 7, Ljubljana. Radoičič, R., 1964, Mikropaleontološke odlike i stratigrafska korelacija nekih jurskih stubova spoljašnih Dinarida. Nafta 15, Zagreb. Sartoni, S. et Crescenti, U., 1962, Ricerche biostratigrafiche nel Mesozoico delTAppennino Meridionale. Giorn. Geol., 29, Bologna, S r i b a r, L., 1962, Mikropaleon to loški pregled vzorcev z lista Ribnica 52. Arhiv Geološkega zavoda v Ljubljani. Sribar, L., 1964, Mikrofacies mezozojskih skladov Slovenije, I. faza. Arhiv Geološkega zavoda v Ljubljani. Sribar, L., 1965, Mikrofacies mezozojskih skladov Slovenije, II. faza. Arhiv Geološkega zavoda v Ljubljani. Weynschenk,R., 1950, Die Jura-Mikrofauna und Flora des Sonn-wendgebirges (Tirol). Innsbruck. -t-1 ^ >« g o a -a K C «1 S a> ■a S S N | ■2, 'c O a IT. X CO £ 3 a a 'a o e tt. fi < i-i 0 O J o w o SI. 2. Orbitopsella praecursor (Gtimbel) 32X, srednja liada, Zagradec-Randol št. zb. 766 a—6737 SI. 3. Textulariidae, 35X, zgornja liada-dogger, Zagradec-Randol št. zb. 568—5741 SI. 4a. Protopeneroplis striata Weynschenk, 75X, spodnji malm, Zagradec-Randol, št. zb. 773—6776 SI. 4 b. Protopeneroplis striata Weynschenk, 75 X, spodnji malm, Zagradec-Randol št. zb. 23—12434 SI. 5. Coscinoconus sp., 35 X, spodnji malm, Zagradec-Ran-dol, št. zb. 711—6761 SI. 6. Clypeina jurassica Favre, 32X, zgornji malm, Za-gradec-Randiol, št. zb. 503—5635 SI. 1. Sphaerocodium borvemanni na površini glavnega dolomita. Staro Apno pri Turjaku. Naravna velikost Fig. 1. Sphaerocodium, bornemanni naturally washed out on the surface of upper dolomite. Staro Apno at Turjak. Natural size GEOLOGIJA 9 BUSER, PLASTI S SFEROKODIJI SI. 2. Zbrusek dolomita z algo Sphaerocodium bornemanni. Povečano 4,5-krat Fig. 2. Thin section of dolomite including alga Sphaerocodium bornemanni. Enlarged 4,5 X GEOLOGIJA 9 BUSER, PLASTI S SFEROKODIJI STAROST PLASTI Z ALGO SPHAEROCODIUM BORNEM AN NI ROTHPLETZ V SLOVENSKIH ZUNANJIH DINARIDIH Stanko Buser Z 1 skioo med tekstom in 2 slikama v prilogi Plasti z algo Sphaerocodium bomemanni Rothpletz so bile v Jugoslaviji prvič odkrite leta 1945. Opisal jih je leta 1952 H e r a k. Iz Slovenije je isti avtor določil prve sferokodije šele leta 1957. Po podatkih geološke literature se sferokodiji v alpskem razvoju triade pojavljajo od zgornjega dela ladinske stopnje (kasian-cordevol) in segajo v zgornjo triado. Rothpletz (1891, 299) in Leuchs (1925,7) pravita, da so te alge najbolj razširjene v kasianskih (cordevol) in posebno še v karnijskih plasteh. Herak (1952, 190) je prvi izrazil mišljenje, da so sferokodiji razširjeni tudi v plasteh noriške stopnje. Rothpletz (1891, 299 in 300) pa jih je našel tudi v plasteh retske stopnje. Sphaerocodium. bomemanni ima kroglast talus s koncentrično zgradbo, podobno oolitni. Na prerezih so lepo vidne posamezne plasti, ki jih predstavljajo enocelična vlakna individuov. Med plastmi, oziroma kroglastimi talusi, so tanki pasovi prikamenine, navadno temnejši kot talusi, ki jih na terenu zato lahko opazimo. Kroglaste plasti talusov povečini obdajajo drobec kamenine ali majhen odlomek lupine. Prve notranje plasti imajo zato več ali manj obliko tujega vključenega telesa, medtem ko so zunanje plasti lepo okrogle, oziroma grudaste. Velikost kroglastih alg je od 1 do 16 milimetrov. Na raznih lokalitetah se dobe tudi različno velike alge. Povečini nastopajo alge tesno druga ob drugi in so kamenotvorne; zato kažejo plasti videz oolitne zgradbe (1. in 2. si.). Pri geološkem kartiranju smo dognali, da se pojavlja horizont s Sphaerocodium bomemanni v slovenskih zunanjih Dinaridih v srednjem delu glavnega dolomita, ki pripada noriški in retski stopnji zgornje triade. Ta dolomit je litološko skoraj povsod enako razvit od spodnjega do zgornjega dela. Na doslej kartiranem ozemlju slovenskih zunanjih Dinaridov so pod glavnim dolomitom povsod plasti karnijske stopnje, ki jih predstavljajo rdečkast peščenjak, argilit, lapor, breča, konglomerat in tufi. Ponekod je razvit v spodnjem delu klastičnih karnijskih sedimentov črn apnenec z vmesnimi glinastimi in lapornatimi plastmi. V teh glinenolapornih plasteh se dobe značilni fosili Pachycardia rugosa Hauer, Trigonodus camiolicus 25 — Geologija St. 9 385 Bitt., Myophoria kefersteini Miin. V zgornjem delu dolomit noriško-retske stopnje postopno prehaja v spodnjejurske plasti. Noriško-retski dolomit je v slovenskih zunanjih Dinaridih tipično skladovit in pasovit ter vsebuje vložke belega zrnatega nepasovitega dolomita. Debelina noriško-retskega dolomita je 1000 do 1500 metrov. Sphaerocodium bornemanni in drugi fosili se navadno pojavljajo v zrnatem dolomitu. Horizont z algami je debel 25 centimetrov do 2 metra. Pri Gornjih Otavah severovzhodno od Cerknice smo- poleg alge' Sphacrocodium bornemanni našli še školjko Conchodus injraliasicus (Wulf.) in polža Worthenia solitaria Benn. Severno od Dol (zahodno od Radeč) pa leži horizont s Conchodus infraliasicus tik pod horizontom z algami, medtem ko nahajamo plasti z megalodontidami in polži drugod nekaj metrov nad horizontom z algami. S tem je dokazano, da pripada horizont z algo Sphaerocodium bornemanni v slovenskih zunanjih Dinaridih povsod noriški stopnji. Algo Sphaerocodium bornemanni smo dobili tudi v spodnjem delu karnijskega črnega lapornatega apnenca na hribu Zaplaz pri Čatežu. To najdišče leži na meji Posavskih gub. Karnijske plasti leže tukaj na belem zrnatem cordevolskem dolomitu. S tem je v Sloveniji sedaj prvikrat najdena ta alga tudi pod noriško-retskim dolomitom. Vendar s tem ni izgubila stratigrafskega pomena za slovenske zunanje Dinaride, kjer jo dobimo samo v glavnem dolomitu. Imeti moramo vedno pred očmi, da je lahko isti. fosil, ki za določeno območje ni vodilen, drugod vodilen, ker se pojavlja v stalnem horizontu. Nad horizontom z algami leži v slovenskih zunanjih Dinaridih Še v znatni debelini litološko popolnoma enak dolomit, ki pripada delno še noriški delno pa že retski stopnji. Po postopnem prehodu glavnega dolomita v plasti spodnje jure sklepamo, da je povsod razvita tudi retska stopnja, ki je pa zaradi pomanjkanja fosilnih ostankov in litološko enako razvitega dolomita ne moremo ločiti od noriške stopnje. Opis važnejših najdišč sferokodijev 3. si. Dolina Bele pri Idriji. V zgornjem delu kanjonske doline, vrezane v glavni dolomit, nastopa v zrnatem dolomitu med pasovitim dolomitom okoli 2 metra debela plast, ki je vsa polna alg Sphaerocodium bornemanni. Ta plast leži okoli 600 metrov nad plastmi karnijske stopnje dokazanimi s fosili. Tik nad horizontom s sferokodiji slede skladi s školjkami Conchodus infraliasicus. Plast z algami se da več ali manj kon-tinuirno slediti na dolžini okoli dva kilometra. Nad horizontom s sferokodiji leže še okoli 500 metrov debele plasti glavnega dolomita, ki na severnem poibočju Trnovskega gozda prehajajo v spodnjeliadne plasti. Godovič. Ob cesti Godovič—Zavratec je v peskolomu zdrobljenega pasovitega dolomita okoli 2,5 metra debel horizont s sferokodiji, ki so zelo lepo ohranjeni. Tudi tukaj leže pod tem dolomitom klastični skladi karnijske stopnje. 0 LJUBLJANA SV IB NO O 0 RADEČE . The tonnage of nickel ore was about 2 000 000 tons at the end of 1963. This deposit contains an enriched ore zone with the highest grade of nickel (4,53 °/o) indicated by garnierite. SOME OF THE ULA-ULO NICKEL CONTENTS Number of Depth of the Average nickel the hole hole, m content, % 36 6,7 1,22 59 3,0 1,27 0/F 6,5 1,77 0/B 9,5 1,76 0/E 6,0 1,39 1/B 3,3 3,70 2yB 13,0 1,40 2/A 11,5 1,09 o/c 0,3 1,69 1/A 20,4 1,95 2'C 3,0 1,08 3/B 6,3 1,41 4-A 12,0 1.88 4,B 5,0 1,77 5/A 5,0 2,31 5/B 10,8 1,90 5/C 4,0 1,35 12 9,6 0,96 13 8,9 0,92 14 8,8 1,45 15 4,2 1,06 1C 7,5 1,38 17 5,0 1,13 18 12,0 0,84 19 8,3 1,43 20 6,0 1,54 21 2,0 1,06 22 4,7 1,39 23 4,0 0,93 26 4,5 1,15 27 8,7 1,11 40 11,2 1,54 41 6,6 2,23 43 3,0 1,05 45 2,0 1,30 47 2,3 1,45 62 5,0 1,12 72 3,4 0,95 95 5,0 1,21 97 5,4 1,98 Average depth 6,61 1,35 Kilta Another deposit of the same type is found 2 km to the south of Ula-UIo. This serpentinite also shows enrichment of nickel in residual soil of the alteration zone. 0 H S > a 1 i—i o H S m > O O r > o o F O r > o H 5d CA > a O S n Dubicha Gudda and Mika This serpentinite residual soil shows enrichments of nickel. The prospecting in this area is carried out at present on a large scale. Monissa Monissa weathered serpentinite and subordinate lateritic soil with nickel contents within 0,5 and 1,1 % is situated in extreme north of the Sidamo-Province pre-Cambrian rocks area situated about 16 km west of Meleka village, which is in turn about 35 km from Kebre Mengist village at the road to Addis Ababa. It could be visited also from Chambi village along the path about 7 km long in northern direction. Chambi village could be reached from Kebre Mengist by road constructed for the gold-bearing areas of Ababa river drainage basin. The nickel-bearing area which is more o-r less identical with the serpentinite is about 5000 m long and 100—500 m wide. The serpentinite is embedded in talc-chlorite-tremolite schist bounded mostly by gneiss. Lolotu Lolotu is located about 32 km south-eastwards of the Adadicotu airfield. The nickel-bearing area is associated with weathered serpentinite and subordinate lateritic soil. The nickel content of samples got by preliminary prospection gave similar results as the samples collected in Monissa. Chabessa Chabessa serpentinite body is similar to Dubicha Gudda serpentinite and is situated between Monissa and Dubicha Gudda about 3 km to the north from Dubicha. The available surface of serpentinite is smaller than in Monissa and Dubicha mountains. Its nickel content in weathered serpentinite is similar to that of Monissa. Tuian Chebi and Aragessa In extreme south of the serpentinite outcrops south of Kenticha the nickel content in weathered serpentinite of two samples amount to 1,5 °/o. * The above described nickel ores of Sidamo have been discovered by nickel bloom. The rock outcrops were attacked by meteoric water, oxidized by air, and decomposed by organic acid deriving from the metabolic activity of plants and animals, a process which may be compared with the oxydation of metals. Prolonged oxidation of nickeliferous minerals on the earth surface, particularly at Tulla, produced nickel green, which could be a hydrous oxide or a hydrosilicate. The apple green tint stain 28 — Geologija St. 9 is in contrast against the pink-grey background of serpentinite. Particularly at Tulla serpentinite outcrops nickel green occurs on the surface of serpentinite as sinters, incrustations, coatings, also as small veins or network of vein lets extending some distance into the serpentinite from its surface. The typical apple green tint staining gave rise to inhabitants of this region to pay attention to the occurrence on which samples have been sent to the Ministry of Mines. Based on favourable result of analysis, prospecting started in the year 1963 at Tulla. The first structural bore hole proved the distribution of nickel in the depth (Table VIII). This hole show that the highest concentration of nickel was found in the depth of 1,4 m — 3,0 m with 1,8% of nickel. In the depth the content of nickel decreases up to 18 m. Small variations within 0,44 and 0,64% have been found in content of nickel in deeper parts of the core, but the content was less than 0,5 % of nickel below 24,7 m. The drilling proceeded up to 79,6 m in serpentinite and proved that any concentration of nickel could be expected in the depth. Based on this bore hole, a large drilling program was set up and carried out in Tulla area, partly with mechanized drilling, partly with pitting and hand boring as the small depths requested to reach serpentinite with less content than 0,5% of nickel vary within 3 m and 13 m. At Ula-Ulo and other serpentinite nickel staining was hidden until the prospecting started. It appeared along the road to the top of Ula-Ulo mountain which cuts the slopes of this mountain. It was mentioned in the primary nickel deposit chapter that the nickel compound originates from the disintegration of the olivine lattice during the process of metamorphism and concentration of nickel in the product of metamorphism. Serpentinite is an alteration product of olivine and pyroxene. The serpentinite is chemically composed of metals (magnesium, iron, nickel) linked with silica in a definite order. Serpentinite contains a very minute amount of nickel which replaces a part of magnesium and iron, and which is probably uniformly distributed throughout the mineral. It represents the initial material from which silicate nickel ore was derived. In order to get the nickel deposits of higher concentration (over 1 % of nickel) compared with the average content of serpentinite (less than 0,5 %) of nickel, process of weathering must take place. During the process of weathering the first element leached out was magnesium, followed by more magnesium together with iron and nickel. The last to be weathered was the silica matrix. All these elements were dissolved by water, which infiltrated underlying rocks through cracks and pores. First precipitated at the very surface of the earth was iron which accumulated in the upper crust between 0 m and 1 m forming a type of brown laterite, being loose if dry, and argillaceous if wet. A part of the iron went farther down to be deposited in the fissures of the rock Veins of crystalline magnetite and amorphous magnetite occur within this layer. These veins usually limit the second layer and introduce the third layer which consists of light partly weathered serpentinite of lower density than fresh serpentinite which has not been decomposed into clay. A characteristic of this zone is the magnesite occurring as white veins in fissures, and minute grains of calcite, as this layer shows weak reaction of hydrochloric acid. The leached serpentinite is nickeliferous only at the upper part near to the second layer where increased contents have been noticed compared with the lower parts of the layer. Farther down, as the above mentioned carbonates begin to appear, the amount of nickel decreases until it reaches the unaltered serpentinite. The Tulla deposit represents a transition type to the fissure type of nickel deposit, where the zoning is not so clearly expressed. However, deposits as Ula-Ulo, Dubicha Mika and Gudda belong to the clearly zoned types of weathered nickeliferous deposits. The subsequent erosion influenced the entire nickeliferous deposit, as it is composed of comparatively loose and easily erodable argillaceous material. Therefore, at some places (Dubicha Mika and partly Dubicha Gudda) the upper layer and a part of second layer were eroded, as the serpentinite with magnetite veins appeared at the surface. In some places only the upper layer is eroded (part of Tulla and Ula-Ulo), as the highest contents of nickel have been found at the surface or near of it. After weathering of serpentinite nickel in the solution was carried deeper compared with iron to be precipitated in the depth of 0,7—1,3 m. Magnesium, however, infiltrated deeper layers of the rock, and it deposited after iron and nickel. Therefore, fissures filled with magnesite were observed. This layer represents the root of the weathering process. Silica began to dissolve only when the serpentinite was completely free of above mentioned metals. While a part of silica remained in situ, the leached parts were gradually deposited in the pores and fissures. The above process gave rise to the following sedimentation characteristics, which are found in all deposits prospected and explored in details (Tulla, Ula-Ulo, Dubicha Mika and Gudda) in more or less clear forms. The lateritic iron layer with transition to ochre occurs in the upper part of the weathered zone. This zone is mostly eroded and only partly preserved. The middle part of the weathered zone is mainly composed of pink, sometimes sandy argillaceous material (clay) with remnants of original serpentinite. This clay is of low plasticity, it is waxlike and greasy if touched. Minute inclusions of octahedra of magnetite and probably of other spinels with traces of platinum could be detected in it, if the material was panned as at Tulla and Ula-Ulo in form of fine black sand (clay which originates from other rocks usually does not yield black sand). By means of the microscopic analysis of Ula-Ulo material veins and stringers of chalcedony were determined in this layer. These veins result from silica deposited in cracks by descending solutions. Secondary (eluvial) chromite deposits The largest residual deposit of chromite was found in Budussa 100 km south of Kebre Mengist. The serpentinite in this area occurs in the environment of the chlorite-tremolite schist and antophyllite rocks (with asbestos) in form of two bodies. Chromite boulders occur in blocks up to 0,5 cu. m in size. Trenching carried out in the year 1960-61 has proved that the eluvial chromite blocks are isolated from mother rock. They have been brought to the surface by gradual erosion of the mother rock which could be talc, as relics of this rock have been found associated with chromite boulders. The reserves of residual chromite amount to maximum 2000 metric tons. The relation between iron and chromium is very favourable and could be considered as a high-grade chromite in respect of its low iron content. As the reserves are too small, the residual deposit has no commercial value. According to Bent or (1963) who visited in the year 1963 the Budussa chromite occurrence, the chromite boulders could not have been transported from afar, as evidenced by their very large size and by the fact that on the highest part of the trench chromite pebbles occur without any admixture of other materials. According to this visitor, there are three possibilities of the origin of the chromite blocks. The first one explains the boulders being formed from at a present eroded primary chromite deposit near the present eluvial deposit. The second possibility assumes the boulders having rolled down from the higher part of Budussa mountain, what seems to be remote, as a survey showed that neither rocks usually associated with chromite nor chromite occur on this hill. The third possibility assumes the chromite blocks derived from an exposure of ultrabasic rocks occurring about 4 km to the NNE. A very small number of chromite pieces occurs at Dubicha Gudda and Dubicha Mika; therefore, the residual chromite deposit has no commercial value. The same may be concluded for Wollabo Valley chromite occurrences. Genesis of nickel-chromium deposits Taking in consideration the above mentioned field data and laboratory investigation, the chromium and nickel are derived from peridotitic magma. The forming of the deposit was as follows: Peridotitic magma Peridotite-magmatic concentration (Olivine with nickel and chromite was formed) Metamorphism (Nickel went into solution and formed various compounds) Serpentinite (Concentration of nickel as well as chromite in serpentinite) Alteration and erosion (A residual clay with garnierite and other nickel compounds is formed. Eluvial chromite deposits near serpentinite were formed by erosion of serpentinite). Summary To improve the mine development and increase the gold production in Ethiopia, in Sidamo province a complex geological-mining development project is being carried out by the Ministry of Mines of the Imperial Ethiopian Government. The main method used was a systematic prospecting in order to increase the gold reserves, planning of mine development, construction of water supply and power supply system, and acquisition of new mining equipment. During geological mapping metamorphosed ultrabasic rocks have been found, and a systematic prospecting and exploration for nickel and chromium minerals is actually carried out. The result will be the increase of gold production by mechanized projects and the limiting of handwork production on placers unsuitable for mine development. REFERENCES A s t r u p, J., 1948, Inedited report on exploration by drilling of the alluvial gold in Kebre Mengist Valley. B e n t o r, Y. K., 1963, Ethiopia Preliminary Report, July 20 — August 19. Doorninck, N. H., 1950, Inedited Reports, Addis Ababa. Hinterlechner, A., 1956, Petrografsko poročilo o vzorcih iz Adole in okolice, Ljubljana. Jelene, D., 1956, Incdited Report on Mining problems of Ethiopia, Addis Ababa. Jelene, D., 1956, Inedited Report .cm Kebre Mengist goldfields, Addis Ababa. Jelene, D.f 1965, Mineral Occurences of Ethiopia, Edited by Ministry of Mines, Addis Ababa. Krenkel, 1925, Geologie Afrikas, in Geologie der Erde, Berlin. K i t a i s k y , Prospecting for nickel, Moscow. Kleindienst, M., 1960, Inedited report on review of Bore Project, Addis Ababa. Nat o m a s Co., 1956, Inedated report on placer gold of Ethiopia, Add.s Ababa. THE IRON AND MANGANESE ORE DEPOSITS IN ETHIOPIA Milan Hamrla With 18 photographs, 9 sketch maps and 6 tables Introduction Ethiopia is still one of the few African countries without a well active Public Geological survey (Dixey, 1960). Accordingly, the mineral potential of the country is known only partly, and the activity in mineral exploration develops still on occurrences and deposits known for a long time ago. The prospection from the ancient times revealed many of the existing deposits, especially those visible at the surface. Besides gold which was the primary target of the ancient prospector, also iron ore deserved special attention by the native people in its struggle to get provided with weapons and utensils. The native people exploited and smelted iron ore at numerous localities for centuries and still nowadays the primitive technique of smelting by use of charcoal can be seen. With the beginning of modern time the new-comers became interested in searching for iron and other mineral raw-materials in the country. During the Italian occupation serious efforts have been made to assess and to develop iron ore deposits, but without practical success. No new large and economically important deposit has been discovered and developed. Also in the post-war time no additional iron ore deposit was found and the assessment of the known deposits was directed to the idea of errection a modern steel-mill industry. Presently, there is only one small steel foundry and roUing mill operating from 1962 at Akaki near Addis Ababa, and having a capacity of 50 tons per day only. Scrap iron is used prevailingly with a small amount of limonite ore from Entoto hill. Following the suggestions of the Second five year Plan on the urgent priority and special significance for iron prospecting, extensive exploration was undertaken in the last two years by the Ministry of mines, and directed toward verifying the reserves of iron ore in the known deposits. In the Plan, however, the construction of a steel and metal industry based on domestic ore is planned for the end of 1967. The first step of renewed reconnaissance and exploration of the main part of known deposits is in general finished. Further exploration, being in course now, is carried out by specialised groups of foreign contractors and is directed toward the assessment of the eventual economic reserves by means of geophysical and drilling techniques. The iron and manganese ores hitherto known in Ethiopia are oxidic only. The deposits belong to different types as it will be described in the following. This article presents a brief summary of essential data on the principal iron and manganese ore occurrences in Ethiopia known till the beginning of 1964. The description of individual deposits is given mainly on the basis of personal field observation as well as own sampling and microscopic examination, supplemented by additional data from published literature and other sources. For each deposit a very short history of exploration is mentioned. The geological mode of occurrences is described and the deposits are classified regarding the origin. The reserves are estimated regarding the type of deposit and the degree of exploration. The measured tonnages have been calculated for some of the deposits. Three of the occurrences treated have not been visited and verified by the author in the field. Several new chemical analyses hav been made in the Chemical laboratory of the Ministry of mines. The other analyses and data used in preparing this article were derived from the listed references. The author's personal view regarding the economic appraisal of the deposits is not necessarily the opinion of any other person. GENERAL DATA ON THE IRON AND MANGANESE OCCURRENCES IN ETHIOPIA Geological setting of the country About one quarter of Ethiopia's surface consists of pre-Cambrian crystalline rocks of sedimentary and igneous origin. Different lithological types can be distinguished. A highly metamorphosed series, having resulted from high-grade regional metamorphism, is composed of gneisses, mica-shists and amphibolites. An apparently less metamorphosed para-series is composed of different schistose rocks including quartzites and crystalline limestones. Both series are intruded by acid and basic igneous masses. The whole crystalline basement is strongly folded and faulted with the general N—S trend of foliation. Stratigraphically, no exact differentiation has been performed till today, and the correlation of the rocks with metamorphic facies of other parts of Africa is not yet solved (Furon, 1960). In Africa the metalliferous mineral occurrences are almost all associated with the metamorphic rocks of pre-Cambrian. The same can be expected for Ethiopia. The relatively most important primary iron ore deposits hitherto known in the country are bound to the metamorphic complex. The pre-Cambrian basement was erroded to a peneplain and overlain unconformably by the sediments of Mesozoic and volcanic rocks of 3U' M* iS• *0' Fig. 1. Generalized geological map of Ethiopia (after P. Mohr), showing principal iron and manganese deposits SI. 1. Splošna geološka karta Etiopije (po P. Mohru) z glavnimi nahajališči železa in mangana GEOLOGIJA 9 HAMRLA: IRON AND MANGANESE DEPOSITS IN ETHIOPIA Tertiary. Mesozoic sediments spread in general in the eastern part of the country and cover a good another quarter of the country's surface. They are composed of marine sandstones, limestones and evaporitic sediments prevailingly. Cainozoic is represented by sedimentary rocks of Tertiary which are confined to the extreme east of the country and are of marine origin prevailingly. The most extensive Tertiary formation is represented by extrusive volcanic rocks of Trap series which extend over the Mesozoic and pre-Cambrian formations. Nearly half of the country's surface is covered by thick layers of volcanic rocks of Trap series consisting of basalts prevailingly with some more acid rocks and pyroclastics. These rocks build up the high plateau in the central part of the country. In Tertiary age the upwarping and sinking movements started and shaped the present forms of mountains and rifts. The volcanism continued during Quaternary in which period also marine, lacustrine and fluviatile depositions were sedimented in local areas and basins. Recent volcanic activity is known in this part of Africa and the youngest volcanic rocks are named Aden series. During the emersion periods the process of weathering alteration, known as lateritization, took place over the pre-Cambrian complex as well as Mesozoic sedimentary and Cainozodc volcanic formations. The alteration processes played an important part in the formation of secondary iron and manganese accumulations. Distribution and kinds of deposits The existing deposits are primary and secondary in origin. As to the geological mode of the occurrences the relatively most promissing and high-grade ores are confined to the pre-Cambrian metamorphic rocks. The primary deposits are known to exist in Eritrea and Wollega provinces. The pre-Cambrian basement complex must be considered as the potentially most favourable environment to contain primary high-grade ore, but also secondary low-grade ore. The next favourable environment is represented by the volcanic rocks of Trap series. The existing low-grade iron ores are an alteration product and resulted from weathering and leaching under the influence of the descending meteoric waters. In the same way the secondary iron concentrations formed in the clastic Mesozoic sediments cemented by ferruginous cement. Hydrothermal iron mineralizations in pre-Cmabrian rocks do exist too, being of ascendent k a ta thermal and telethermal or rather hot-spring character. The depositions of manganese have much less extent in comparison with iron. Only one primary deposit is known to exist in marine sediments of young geologic age. Other manganese occurrences are connected with the secondary iron depositions. Iron and manganese behave in a similar manner in the exogenic cycle and concentrations of both metals in residual deposits are frequent. The distribution of deposits and occurrences treated is given in the generalized geological map of Ethiopia (Fig. 1.). The deposits of iron and manganese belong to the varied types of genesis. The iron ores are magnetitic, hematitic and limonitic and the manganese ores are oxidic too, being more or less ferruginous. The following genetical types of deposits have been found in Ethiopia. Iron 1. Metamorphic type is of primary sedimentary origin and subsequently mineralogically and texturally altered by regional meta-morphism. 2. Combined metamorphic-contact metasomatic type was formed by a combination of sedimentation, metamorphism and metasomatism. 3. Residual concentration type, having resulted from decomposition and leaching of extrusive or other ferruginous siliceous rocks. 4. Hydrothermal type is of katathermal and telethermal (hot-spring) character. 5. Magmatic type is inferred only and not cleared enough. Manganese 1. Residual concentration type1 is closestly connected with secondary iron accumulations. 2. Hydrothermal type is closestly connected with telethermal iron. 3. Sedimentary type is of marine origin. DESCRIPTION OF DEPOSITS AND OCCURRENCES IRON 1. Metamorphic type Koree — Gollisso — Nejo zone General. Regarding the possible reserves of high-grade iron ore this zone in Wollega province seems to be one of the relatively most promissing areas in the country. Its center is in the Aira area north of Yubdo. A small primitive smelting activity is reported to have existed there from the former time and exists still nowadays. No published data are available on these occurrences except M u r d o c k (1960), who dropped some lines on these deposits, having considered them as small and irregular replacements in dunite and not persistent at depth. His opinion was that none of the occurrences in Wollega are of any importance except for strictly local use for primitive smelting, such as was formerly carried out there. Fig. 2. Geological sketch map of the iron ore-bearing zone Koree-Gollisao-Nejo in Wollega SI. 2. Geološka skica nahajališč železove rude v coni Koree-Gollisso-Nejo v Wollegi Fig. 3. View of Koree outcrop on the top of hill SI. 3. Pogled na izdanek Koree vrh griča The zone was not searched in the past due to the lack of suitable communications and thus little prospects of economic exploitation. In the season 1963 extensive prospection was carried out by the Ministry of mines. Recently (spring 1964) detailed geological and geophysical (magnetometer survey) exploration started with the aim to assess more exactly the deposits, and to provide the basis for an eventual further drilling program. It, was carried out by the Yugoslav RUDIS company. Geologically the region is built up by pre-Cambrian rocks of apparently younger less metamorphosed series and overlain by basaltic cover. Petrographically para-rocks as mica-schist, chlorite-schist, amphi-bole-schist, phyllites and quartzites prevail, having a constant foliation of abcut 15" and dipping steeply west. Igneous rocks of ultrabasic, basic and acid types are included as well as some gneisses. The general situation of the zone is given in the enclosed map (Fig. 2.). Ore outcrops are known to extend in a zone of several tens of kilometers in lenght. Lenslike ore bodies occur included in the crystalline rocks. Besides outcrops in situ also secondary ore can be found as large boulders. The possibility exists that the zone continues southwards as well as northwards from the prospected and reconnoitred area. No doubt a mineralized zone following the general NNE—SSW trend of foliation in the basement complex is in question. The magnetitic-martitic ore is coarse crystalline, bluish-black in colour but the strike is reddish due to the high grade of martitization. On the surface rare incrustations with limonite occur sometimes. Description. The most southern outcrop of ore at Koree some 16 km south of Yubdo is the biggest in dimensions from all existing in the discussed zone. It consists of a lens of about 200 m of visible lenght, having a thickness of several meters. The outcrop forms a well pronounced topographic ridge, striking 35° and dipping nearly vertically (Fig. 3.). The prolongation of the ore body for some additional 100 m is assumed, the outcrop being hidden under the thick cover of residual soil. The ore consists of magnetite and martite and appears in big angular blocks with quartzite banding, being more or less impure and limonitized. About 500 m southeast from the outcrop large boulders of magnetite are scattered on a pretty great surface, several of them of considerable size. The boulders are not in situ. They form secondary deposit derived either from the existing Koree outcrop or another one burried under the soil in the vicinity. Anyhow, the boulders could not have been transported from afar. The existing reserves at Koree can be estimated to some 150 000 to 200 000 tons of ore, provided the depth of the lens is about one half of the lenght and a lenslike body is supposed. Additionally, several thousands tons of ore are deposited as boulders on secondary place. The next known outcrop of ore exists about 1,5 to 2 km northwest of Yubdo. On a hill slope just beneath the volcanic cover scattered boulders and pieces of ore can be found on a surface 300 m by 60 m approximately. Some of them are very large in size, weighing several tons each (Fig. 4.). It looks very probable that at least a part of ore is not in situ there, Fig. 4. Boulders of magnetite at Yubdo outcrop SI. 4. Magnetitni bloki na izdanku Yubdo but due to the very large size of the blocks they could "hot have been transported from afar. The primary deposit has to be somewhere very near, burried under the residual soil or even basaltic capping. The coarsegrained ore seems to be clean with some inclusions of quartz. About 650 m northwards from this place iron ore in situ crops out in a trench made by natives, which exploited the ore. The ore body here might be about 30 m in lenght and several meters thick, judging on the dimensions of the trench. Its strike might be about 45° and dip nearly vertical. The ore consists of impure limonitized magnetite intermingled with banded quartzite. It is possible that the lens continues southwards under the volcanic cover, which begins just at the end of the trench. The form as well as the character of the deposit could not be definitely established by surface examination only. The existing reserves at Yubdo locality might not exceed the general estimate of several hundreds of thousand tons at maximum, taking into consideration the assumption the ore is in situ prevailingly. If this is not the fact the reserves are much smaller. Several kilometers east from Aira Mission and some 16 km north of Yubdo the Gordana Katcho hill is built up of quartzite, chlorite-schist and mica-schist. On the hill the traces of former exploitation can be seen in form of a trench, striking conformably with the foliation of the metamorphic complex. The trench is about 100 m long and variable in width with several meters on average. Although it is filled up with earth and grown over by vegetation, the blocks and pieces of magnetite can be seen. Bands of magnetite are included in white quartzite indicating the genetic connection of both rocks and minerals. The traces of an exploitation in limited extent can be found also on the western slope of the hill perpendicular to the trend of the mineralized zone. The exposition of the outcrop is bad and an estimation of probable reserves difficult. It could be assumed that several tens of thousand tons of ore might exist there, depending on the not clear dimensions of the ore body. The next outcrop at the locality Chago some 5 km south of Gollisso has a lenght of about 300 m and a width of several meters. Former exploitation by natives is evident and remnants of smelting-furnace can be seen too. The area is strongly covered by residual soil and on some places magnetite ore is to be seen in large block, being very compact and of the same appearance as on the other spots described as above. The trench follows the foliation of the metamorphic rocks, being in general 15° to 20°. The preliminary tonnage estimate of reserves might be analogous to that of Koree, amounting from 100 000 to 200 000 tons of ore. In the area east of Nejo magnetite boulders can be found at several localities (Gambo, Kata valley, Tullu Adere), but there is also ore in situ in form of smaller lenslike outcrops. The ore is of the same appearance and composition as in the other localities described above. The geological environment is more or less the same and the quartzitic and schistose rocks of the basement prevail. A prospection is in course to establish the position and the dimensions of the existing outcrops. For the time being a very rough tonnage estimate of several tens of thousand tons of inferred ore can be assumed for this area. Analyses. Several samples of magnetitic-martitic ore from Wollega have been analysed in 1962 (analyst A. Regan). Table 1. gives the composition of the chip samples of selected clean ore from different localities. Table 1 1. tabela Locality Fe TiOa SiOa p2o5 S MnO Koree 71,6 0,0 0,82 0,06 0,09 0,09 Yubdo 70,9 tr. 1,2 0,08 tr. 0,12 Gordana Katcha 70,8 tr. 3,1 0,03 0,05 0,23 Chago 68,8 tr. 1,8 0,14 tr. 0,12 Nejo (Kata) 65,2 tr. 8,7 Several additional chip samples have been analysed in the laboratory, giving the same size-order in the quantity of the components. In Wollega a rich magnetitic-hematitic ore is in question, very low in sulphur and in phosphorus. The percentage of silica is low in samples of clean ore, but on average it can be expected higher owing to the variable inclusions of quartz and quartzitic mother rock to which the ore is bound. Polished sections of ore have been examined under the microscope in order to provide additional information about the processes of its formation. The microscope reveals a rather porous coarsegrained ore of largely martitized magnetite (PI. 1, Fig. 1.). The magnetite is almost completely oxidized to hematite in form of lamellae, following the (111) planes of magnetite. The alteration is more pronounced at margins of magnetite crystals and martite extends irregularly along cracks into magnetite. With progressive martitization the lamellae broaden and very often only residual areas of magnetite remain. Limenite replaces martitized magnetite here and there, forming rims and irregular bodies .Quartz grains can be found in the ore, concentrated in bands sometimes. An important feature is the exceptional appearance of small roundish inclusions of pyrite and chalcopyrite in the middle of unaltered magnetite grains. Origin. The intimate connection of ore to the parametamorphic rocks consisting of white quartzite and other schistose rocks is evident at all find-spots where magnetitic ore occurs. The ore zone and the ore bodies run parallel with the foliation of the metamorphic complex. The outcroping portion of the ore lenses is extremely altered to martite due to the supergene oxidation of magnetite. There is no doubt that the ore is singenetic with the adjacent rocks of originally sedimentary series. This has been strongly folded and metamorphosed by regional and dynamic metamorphism, accompanied by granitic and other intrusions. Metamorphism entailed mineralogical and textural changes of the primary sediments the "bedding" of which is still discernible in metamorphosed rocks. The paragenesis of the present ore is simple and the magnetite as well as the quartz waste is recrystallized. The sulphides might be primary in origin, and the presence of rare small grains of pyrite and chalcopyrite in the ore could be due to the conditions of primary sedimentation rather than having been introduced later by thermal solutions. There is no other evidence of any hydrothermal activity. Accordingly, the iron ore occurrences in this part of Wollega belong to the metamorphic type of deposits, being derived from a former sedimentary accumulation and subsequent concentration of iron. The question about the primary sedimentary environment and the form in which iron was present originally is difficult to explain. The idea that the original beds of iron formation could belong to epicontinental sediments seems the most probable. Iron may have precipitated and concentrated either as sedimentary oxides or even iron silicates. The attribution of iron to a magmatic source as for instance exhalative activity on the sea floor is less probable. Since the formation the iron-bearing sediments were subjected to extensive metamorphism and re-crystallisation, having converted the primary iron concentration into magnetite. The uncertainity as to the details of origin of this ancient deposit is a direct consequence of its long and complex geological history and this shall be kept in mind when considering the genesis of pre-Cambrian deposits. Reserves. No accurate tonnage estimate of the whole zone is possible before the full program of detailed survey, including drilling, will be carried out. For the time being the presence of ore is known on the above described localities only. The estimated reserves are given as approximate figures in the Table 2. Table 2 2. tabela Estimated reserves (tons) Lccalitv Measured Inferred (min.) (max.) Koree 50 000 100 000 150 000 Yubdo 20 000 50 000 300 000 Cordana Katcho 10 000 40 000 100 000 Chago 80 000 100 000 200 000 Nejo (east) — — 50 000 Total 160 000 290 000 800 000 The quantity of existing reserves for single locality can not be expected more than several hundreds of thousand tons at maximum. The whole zone must be ranged accordingly to small-size iron deposit with a total tonnage of about half a million or so tons of high-grade iron ore. The lenght of the zone is about 70 km and the total lenght of the visible outcrops 750 m only. Billa Approximately 2 to 3 km east of the village Billa in Bogi district in Wollega a pronounced barren mountainous ridge extends (Fig. 5). It is composed of compact light grey quartzite, having a strike of about 10° and dipping apparently very steep west. On the western slope of the ridge several more or less limonitized quartzitic and schistose rocks can be found in a 100 to 200 m wide zone, containing even pure limonitic Fig. 5. View of Billa ridge with scattered pebbles of limonite SI. 5. Pogled na greben Billa z razmetanimi kosi limonita pieces and debris. A banding in the metamorphic strata can be seen and the schistose rocks alternate with layers richer in iron oxide. The lenght of this zone is about 1,5 km. The average iron content is relatively low. It is possible that in the series of alternating strata some of them contain a higher content of iron. Genetically the iron concentrations at this locality are in general bound to the zone of metamorphic rocks as described above. The ferruginous quartzite and schist are of sedimentary origin and subsequently recrystallized by regional metamorphism. The quartzite might be metamorphosed originally arenaceous sediment. The local concentration of limonite found in this place is secondary in origin and has formed by leaching and precipitation of iron out of the primary mother rocks. Chip samples of ore have been analysed, containing even 56 °/o of iron and 3 to 5 % of silica, but these figures can not be regarded as average. The iron content varies from place to place, being in average very low. 29 — Geologija št. 9 449 For the time being it is believed that the iron ore occurrence at Billa is of no economical value due to the low iron percentage. The existence of sedimentary-metamorphic iron occurrences in Wol-lega is, however, an interesting phenomenon due to the fact that many of the significant world's iron deposits belong to this type, which usually contains high-grade iron ore. In South Africa and especially in recent time in West Africa enormous deposits of this type have been discovered (Finn, 1964). In the northern prolongation of Billa ridge some 12 km away of it an analogous iron concentration was found at Tullu Bollale, having the same appearance as that of Billa ridge. Hematitic schist was observed also along the main road to Nejo several kilometers before the town. The iron contents is low. The rocks are reddish-brown and well schistose. Ferruginous schist does exist also in the vicinity of Gollisso. The conclusion can be made that in this part of Wollega several ferruginous schistose horizons appear the iron contents of which is disseminated very irregularly, and here and there concentrated to rich but rather small lenslike ore bodies. 2. Metamorphic — contact metasomatic type Falcat — Agametta zone General. Regarding the geological information available for the time being the most interesting and potentially important might be the iron ore occurrences in Eritrea. Lenslike ore bodies of high-grade magnetitic ore were known for many years to extend at several localities, especially in the area Sabub-Agametta about 40 km east of Asmara, and in the extreme northern part of Eritrea in the Falcat area. Several new ore occurrences have been found in the Gumhod area during the prospecting campaign carried out in 1963 by the Ministry of mines. It looks very probable that additional ore bodies could be found by systematic work in the mountainous and partly extremely hard accessible parts of this province. The data on investigations carried out formerly on these iron ore-bearing areas (Fig. 6.) are summarized by Us on i (1952). In 1919/20 several pits and trenches were dug in Agametta area. Extensive exploration was carried out immediately before War II, applying magnetometer survey too. The reserves were estimated to 2,5 million tons. In 1956 the German KRUPP company assesed the reserves to be probably beyond the 2,5 million tons. In 1963 the Ministry of mines engaged the Yugoslav RUDIS company to explore definitely the 100 sq. km large area between Sabub and Agametta in the most southern part of the ore-bearing zone. At the same time the reconnaissance, prospecting and preliminary studies in the adjacent areas covering totally over 1800 sq. km were carried out by the Ministry of mines. The aim of this Fig. 6. Sketch map of iron ore-bearing areas in north eastern Eritrea SI. 6. Karta območij železovih nahajališč v severovzhodni Eritreji N LEGEND LEGENDA -71 CRYSTALLINE ROCKS LA METAMORFNE KAMENINE SCALE HERILO GNEISSES AND GRANITES GMAJSI IN GRANITI IRON ORE (MAGNETITE) ŽELEZOVA RUDA (MAGNETU) MARBLE MARMOR COPPER IMPREGNATIONS IMPREGNACIJE Z BAKROM 24 kil o m« t res Fig. 7. Provisional geological sketch map of the Falcat area (After A, Cavagnari, 1919) SI. 7. Približna geološka skica območja Falcat. (Po A. Cavagnariju, 1919) activity was to provide the preliminary basis for the eventual further investigations. The northern ore deposits in the Falcat region could not be visited by the author in 1963. The deposits were studied in the past mainly by Bibollini (Usoni, 1952). The general geological situation is evident from an unreliable sketch by Cavagnari (Fig. 7.). In 1940/41 the Italian RIMIFER company explored the deposits geologically and geo-physically without having discovered new ore bodies. No definite view can be deduced from Usoni's data regarding the economic importance of these deposits, and the reserves were estimated to 200 000 to 300.000 tons only. In judging the potential possibility of the whole ore-bearing zone the deposits in the Falcat area must be explored and studied definitely in the shortest possible time. According to the Italian geologists the iron ores of Agametta as well as of the northern deposits in the Falcat area are pyrometasomatic in origin and related to silicic intrusions. KRUPP found obvious indications of the sedimentary character of the ore in Agametta area. RUDIS (1963) interpreted the origin of the ore in connection with the exhalative volcanic processes in the shallow sea. Subsequently hematite was transformed into magnetite by regional metamorphic and contact metamorphic processes. Description. Geologically the Gumhod-Agametta area in the eastern part of the central Eritrea consists of pre-Cambrian rocks of presumably low-grade metamorphism similar to those in Wollega. The most important rock-types are parametamorphic schistose rocks varying from almost unaltered arenaceous sedimentary rocks to high-grade metamorphosed gneiss fades. The inclusions of calcareous lenses occur often in the basement complex, the foliation of which is in general NNW—SSE in this part of Eritrea. Granitic, pegmatitic and differentiated intrusive rocks are included. On the plateau south of Asmara basalt capping covers the basement rocks, and in the coastal part of Eritrea young Tertiary sediments and basaltic lavas spread locally over them. The existing magnetitic ore is prevailingly massive and occurs in big angular blocks (Fig. 8.). Texturally it is coarse-grained but also finegrained or in the form of banded ferruginous quartzite and schist. The latest shows here and there also a well defined banding with quartz-rich layers alternating with iron oxide-rich layers. Also the alternation of magnetite layers with schistose chlorite-schist and other schists is not Fig. 8. Outcrop of magnetite ore at Agametta SI. 8. Izdanek magnetitne rude v Agametti Fig. 9. Outcrop of sehistose magnetite ore at Dongollo basso SI. 9. Izdanek skrilave magnetitne rude v Dongollo bassu seldom to be seen. This banding is without doubt an original sedimentary layering, accentuated perhaps by metamorphic recrystallization. Also the fine-grained magnetite ore shows a very fine banding parallel to the folliation of the sedimentary complex (Fig. 9.). The coarse-grained ore is more clean and the banding seems to be less pronounced. In the northern part of the zone near Gumhod the ore layers consist of alternating bands of magnetite and schistose rocks. The schistose textured ore is intermingled with green chlorite-schist and quartz layers. The southern part of the ore-bearing zone between Sabub and Agametta is built up by different low-grade metamorphic rocks, which contain several lenslike iron ore bodies, following the general foliation in the metamorphic series. In general some ten groups of ore lenses exist there, occurring in different levels in the ore-bearing horizon. According to RUDIS (1963) the ore bodies have the predominant lenghts between 5 and 25 m and the thicknesses exceed exceptionally more than 1 m. Schistose metamorphic rocks contact larger bosses of granodiorite and granite porphyry. A narrow zone of older basic extrusive rocks occurs in the basement complex and RUDIS believes these rocks might be genetically related to the granodiorite as well as to the iron ore. An important feature is the presence of skarns, which are not always connected to the calcareous lenses occurring within the metamorphic series. Besides the locally abundant quartz, garnet, epidote and other silicates also grains of sulphides and patches of copper carbonates occur in this type of ore mineralization. Malachite was found also in small quartz veinlets crossing the metamorphic rocks. Near Dongollo basso a completely isolated lens of banded magnetite ore was found on the Gahar hill, having a lenght of 15 m and a maximal width of 1,5 m. Several kilometers to the north another small outcrop of ore exists near Ailet. Both are included in the foliated schistose rocks. In the Gumhod area several new magnetite occurrences have been found during prospection. They have the same morphological features as those in Sabub-Agametta area, being characterised by scarse small- H 270/70 ORE LENSES OF MARTITIZED MAGNETITE v CHLORITE SHISTS N SCALE MERILO 10 20 30 40 SO metres Fig. 10. Field-sketch of lenslike iron ore occurrence near Gumhod SI. 10. Terenska skica lecastih teles železove rude pri Gumhodu Fig. 11. Outcropping small lenslike ore bodies near Gumhcd SI. 11. Izdanek majhnih lečastih rudnih teles pri Gumhodu sized lenslike ore bodies lying in the strike of the metamorphic complex There is no doubt the occurrences belong to the same ore-bearing zone Three groups of ore lenses have been found there and the group Gumhod I is shown in the sketch (Fig. 10.) as well as in the photo (Fig. 11.). The area between Sabub and Gumhod is represented by a plain covered by sands and torrential piedmont gravels. The thickness of this cover can be estimated to several meters on average. The continuation of the ore-bearing zone along this 20 km long area between the northern and southern outcrops is very probable, however, composed of the eventual small groups of ore lenses. The possible existence of ore under this alluvial cover might be partly proved by a 600 m long magnetic anomaly discovered by RUDIS's magnetometer survey near Fort Am-batocan (RUDIS, 1964). This ore-bearing zone continues in all probability further to the NNW following the general trend of the basement complex. Magnetite sands are known along the sea-shore at Mersa Gulbub in the Northern desert Future efforts shall be directed towards possible new discoveries of ore in this area. Owing to the fact that this region is far and very hard to access only a well organized and equiped terrestrial prospection could bring results. In the northern part of Eritrea, about 180 km north of Asmara similar magnetite deposits occur at Walet Shek and Mont Tullului in the region of Falcat river. The iron ore occurrences of Falcat-Mont Tullului area and others are described by Usoni (1952), following mainly Bi- bolini's data. Considering also additional data on these areas the conclusion can be made, that the geological situation in general does not differ from that in the Gumhod-Agametta area, except perhaps more accentuated skarn character of the deposits. Magnetite lenses occur everywhere in the closest contact with marble, having both the forms of elongate lenslike bodies. The strike of the basement complex might be there NE—SW and the zone of interest several tens of kilometers in lenght. The deposits are described to be typical contact-metasomatic in type with large formation of epidote, garnet and perhaps ilvaite, the minerals replacing calcite. The mineralization is thought to be due to hydrothermal solutions derived from porphyric extrusions as well as granodiorite or other igneous masses in depth in the vicinity. The lenght of lenslike iron ore bodies may vary between 100 m and 300 m, having the thicknesses of about 10 m as maximum. The presence of iron and copper sulphides is indicated (Us oni, 1952). From Cavagnari's sketch (Fig. 7.) the copper mineralizations look to be well delimited. Specular hematite may occur in the Falcat ore too. Analyses. KRUPP analysed in 1956 seven grab samples of iron ore from Agametta area. The results would give an average composition of ore as follows (in percent): Fe .... 58 SiOz ... 14 P . . . . 0,047 O . . . . 0,018 Additionally, three chip samples of good ore from Sabub-Agametta area have been analysed in the Chemical laboratory of the Ministry of mines. The results are given in the Table 3 (in percent): Table 3 3. tabela No. Fe Si02 Ca Mg a12o3 p Ti MnO Cu so4 250 47,04 22,82 0,00 0,00 0,53 0,02 0,00 0,54 tr. tr. 251 47,50 30,70 0,00 0,00 0,23 0,044 0,00 0,40 tr. tr. 253 68,13 2,30 0,00 0,00 0,20 0,017 0,00 0,35 tr. tr. The percentages of iron and silica are variable and depend on picked samples. It could be estimated that an average contents of iron would vary between 50 and 65 °/o and that of silica between 10 and 20 °/o respectively in the representative samples, which, however, have not yet been systematically taken and examined. Small contents of phosphorus, sulphur and other admixtures make the composition of ore excellent. Many samples of ore as well as other rocks were examined under the microscope as polished and thin sections. As to the ore there are two types to be distinguished: banded magnetite-martite ore and magnetite with skarns. It can be said, in general, that the banded ore consists of granoblastic recrystallized agregate of magnetite and quartz prevailingly. Magnetite in form of allotriomorphic fine grains is concentrated in bands but also dispersed in quartz matrix (PI. 1, Fig. 2.). Magnetite is always martitized, and martite spreads along the grain boundaries and fissures or follows the planes (111) of magnetite in form of lamellae. Some rare inclusions of chlorite, mica, amphibole, epidote and calcite are present. The blastic grain structure of the rocks, which vary from magnetite-bearing quartzite on one side to dense granular magnetite on the other, is due to the metamorphic recrystallization. Big crystalls of epidote occur in the banded rocks sometimes and later quartz fills the cracks and fissures, proving additional hydrothermal processes in the ore. Besides very advanced martitization of magnetitic grains distinct lamellar hematite occur too and can be seen even by unaided eye. The impression is got the lamellar hematite might be due to a special crystallization phenomenon undipendent from that of martitization of magnetite. Lamellar hematite is distinguished by very porous texture. The presence of sulphides in banded ore is another important feature. Rare isometric crystals of pyrite are spread allong banding in quartz matrix. They are much bigger than the average size of magnetite crystals. The great part of these grains appear already completely altered to zoned limonite which spreads also along fine fissures in the ore. Homeoblastic fine-grained quartz matrix gets disturbed along the margins of these crystals and longish quartz grains are oriented perpendicularly to the margins of sulphide grains. Pyrite crystals, having more than 1 mm in size, occur in the bordering zones with marble too. Normally they are pseudomorphoses after pyrite which can be found within limonite in form of small relicts only. It looks that the sulphides have been introduced with a later generation of quartz due to the hydrothermal processes which produced skarns. On the other side small roundish and elongate grains of chalcopyrite occur in the magnetite grains as well as in the martitized parts of it (PI. II, Fig. 1.). The small gold-yellow bodies are distributed very scarcely and irregularly. Their direction seems to be here and there parallel to that of the martite lamellae. The size of these grains which are well delimited from the surronding magnetite, is generally less than 0,01 mm, and the maximum not more than 0,03 mm. Malachite is concentrated as secondary filling in fissures and cracks together with the supergene iron oxides. There is no certainity regarding the textural relation of copper and iron minerals. The intimate relation of both minerals could point out that copper might be primary in origin and syngenetic with iron. This relation is not yet studied in details and sufficiently explained for the time being. The skarn type of ore consists of garnet, epidote, amphibol, prevailing quartz and magnetite (PI. II, Fig. 2.). The microscope reveals the idio-morphic garnet and epidote cemented by magnetite and a later quartz. The idiomorphic garnet crystals show often skeletonlike forms with oriented bandsgrowth in quartz. This is a proof of more or less simultaneous crystallization whereupon magnetite crystallized apparently as the last of the components. Magnetite is always allotriomorphic. It can be found also in the center of garnet crystals. Origin. The information gathered hitherto points out to the explanation of the origin of deposits in the following way. The main part g>f iron in the existing ore bodies is of primary sedimentary origin. It was deposited in the ancient marine basin where the metasediments of the present pre-Cambrian complex originated. A small amount of copper might have been deposited simoultaneously with iron. The original form in which these two metals might have been precipitated is unknown. According to RUDIS (1963) some indications for an exhalative iron origin might exist. Regarding sedimentary copper minerals there are occurrences in the world known where this metal is associated with sedimentary rocks, having originated in the conditions of shallow-water sedimentation. In general there iz much uncertainty as to the sedimentary environment in which the sediments were deposited. The copper mineralization of apparent sedimentary origin seems to be present in Eritrea also at the new discovered occurrence Mont Sacar in the vicinity of Gumhod. The primary depositions containing iron were subsequently subjected to several periods of metamorphism and deformation. They were extensively metamorphosed and recrystalized and iron concentrated to lenslike ore bodies of granoblastic texture. The next hydrothermal replacement mineralization followed, the result of which was the formation of skarns. The mechanism of these events as well as the origin of solutions is not cleared. The components could be either newly brought from magmatic sources or may be simply a remobilization of elements from sedimentary sources already present, without introduction of new material. The solutions may have been derived from the batholitic activity, connected to granodioritic intrusions, younger than the metasediments. The process of martitization is believed to be of supergene origin. As already pointed out a part of hematite is possibly due to hydrothermal activity too. Reserves. The reserves for the most southern part of the iron-bearing zone between Sabub and Agametta have been calculated by RUDIS (1963), and summarized to a global sum of 425 000 tons. Some nine groups of ore lenses in the zone of about 15 km lenght may contain about 124 000 tons of visible and probable ore, and several hundreds of thousand tons of potential possible ore. The enlargement of reserves on account of inferred ore in the depth is not hopeful due to small dimensions of the ore lenses and their scarce displacement in the terrain. As to the visible and probable reserves in the Gumhod area they are calculated to 8530 tons only. The inferred tonnages can be estimated to several tens of thousand tons (Hamrla, 1964). On the basis of the known geological situation in both areas, and on the assumption that the ore might be present in the plain area covered by alluvial sands the tonnage estimate is possible by statistical method. Hence, the reserves of the whole 40 km long zone might amount to about 1 million tons, related to twelve known occurrences and additional nine supposed to exist under the alluvial cover. A depth to 60 m under the surface was considered and the actual relation between the proven and inferred reserves is about 1:7 (Hamrla, 1964). More promissing in reserves might be the Falcat region. The Italian sources report much greater dimensions of the ore bodies from those established in the Gumhod-Agametta area. On the other hand these data seem to be doubtful if compared with the Italian data for Agametta. Additionally the great distance from potential industrial centres as well as from the shore (60 km air-line to Red-sea port Mersa Teclai) makes the immediate economic proficiency of these deposits doubtful even if larger reserves exist. The deposits should be, however, reconnoitred and well assessed in light of experiences gained through detailed geological and geophysical examination of Gumhod-Agametta area. Moreover the whole 180 km long zone between Gumhod and Falcat valley should be prospected and assessed. Other deposits Similar iron ore deposits are reported to exist in Sidamo province in the area of Yavello and Irbi as well as in the zone of Arero and Metacapersa (M u r d o c k , 1960). Magnetitic and hematitic ore is reported to contain 60 to 68 °/o of iron. These localities would be worth to be explored to such an extent that the eventual significance could be assessed. 3. Residual concentration type The occurrences of residual ores are due to the decomposition of silicate rocks in the process of weathering. During the decomposition some leached components go into solution and are carried away, others remain and precipitate in convenient environment. Under conditions characterised by alternating dry and wet seasons, the decomposition is more complete and results in a lateritic soil composed of limonitic and bauxitic components, meanwhile silica is extensively removed. Under favourable climatic and other conditions iron and also manganese may accumulate in this way to form even economic deposits. The concentration of iron in lateritic residue forms residual — lateritic deposit. If the leached components precipitate in open spaces residual — infiltration type originates. Regarding the nature of mother-rock the iron has been leached from the extrusive volcanic rocks and ferruginous siliceous rocks can be distinguished. Extrusive rocks as source oi iron Mai Gudo General. 1'he Mai Gudo area is situated about 60 km to SSE from Jimma in the upper drainage pattern of the Odonitta river. The mountainous area is difficult to access. A 65 km long old road in very bad condition presently connects the locality with the highway some 30 km before Jimma. The deposit consists of many small iron ore occurrences, the most important of which are shown in the enclosed map (Fig. 12.). There is no persistency among the isolated accumulations. Fig. 12. Sketch map of Mai Gudo iron (and manganese) ore occurrences SI. 12. Skica nahajališč železove (in manganove) rude Mai Gudo The ore has been exploited by natives and smelted in a primitive way for a long time ago for the manufacture of tools and weapons. During the Italian occupation considerable mining activity has been carried out and about 20 000 tons of ore were mined. In that time Villaminar estimated the ore reserves, which are cited by Us on i (1952) to amount to 1,2 million tons totally. In 1945 M u r d o c k visited the area and estimated the reserves to 120 000 tons (Murdock, 1960). He pointed out the guess has been made without any real basis. In 1956 an expert of the German KRUPP company reconnoitred the area and found it not worth of any further exploration. At the end of 1962 the Ministry of mines explored the area by pitting and trenching. The occurrences have been found practically without economic importance, being very small in size and insignificant in reserves of ore of medium and low quality (H a m r 1 a, 1963). Additionally, the position of the area is very unfavourable regarding transportation facilities. Description. The large region of Mai Gudo is built up of volcanic rocks of Trap series. Dolerite and olivine-basalt are reported to build the highest parts of the mountains. The prevailing rocks are trachyte-rhyolite. The rocks are extremely weathered and characteristically violet-reddish coloured. Residual soil covers the surface and locally accumulates in considerable thickness. Yellowish-brownish bands and crack-fillings by compact ore could be stated everywhere in the soft weathered country rocks which contain often yellow ochreous and black manganiferous inclusions. The traces of former exploitation in limited extend can be locally found. Melka Sedi is the most important locality among all occurring in this region. Supergene iron ore occurs in the lowest part of a pretty steep slope. Old ditches and trenches are evident in the outcropping area which may have a surface of about 120 m by 100 m. Residual soil covers the weathered rocks, being ferruginous and intensively yellowish-reddish-brown coloured. Thin veins and bulby inclusions of compact ore are frequent. Small bodies of compact limonite are included in yellow earthy ochre containing bluish-black manganese hydroxides as well as layers of grayish-black earthy wad. The structure of ore is breccious and it passes here and there to the residue. It looks that the more compact ore is concentrated in the lowest part of the mineralized zone near the bottom of the slope. The quantitative relation between the compact ore and the waste is in general unfavourable. At Dacano ferriferous concentrations occur in weathered rocks accompanied by manganese oxides. They are quantitatively unsignificant. The outcroping area at Dombova extends on a roughly estimated area 100 m by 80 m. The ore occurrence is similar to Melka Sedi in appearance but smaller and poorer in degree of mineralization. An old trench reveals the prevailing yellowish weathered rocks and banded soil with irregularly concentrated limonite in form of small bulbs and veinlets other than greater blocks and lenses. At Ilche only scarce traces of mineralization exist in residual soil as proved by several pits. At Sassachie weathered yellowish-brown rocks prevail, containing small crack-fillings of iron and manganese oxides. No remarkable ore concentrations exist also at the localities Kurkure, Derabo, Sunaro and Botto, where unimportant local concentrations of compact ore are accumulated in cracked weathered country rock. Veinlike iron ore occurrences were signaled from the locality Aebicha. Iron and manganese oxides are concentrated in tectonically crushed zones, striking 200° to 250° and dipping vertically. They have 10 cm to 40 cm in width. The breccious weathered rocks are cemented with iron oxides as well as with silica, indicating in this way the forms of apparent veins. At the locality Sombo a several centimeters thick lenslike seam of manganese ore was found underlying the clayey overburden. This residual manganese concentration is of theoretical interest only. In general the Mai Gudo ore can be described as mostly unclean and more or less breccious with admixtures of weathered rocks. It consists of hydrated oxides of iron in all varieties from brown hydrohematite on one side to high porous ochre of earthy nature on the other side. The same passes for manganese ore which exhibits stalactitic and spongy masses, but also earthy wad of high porosity can be often observed. Analyses. For Melka Sedi and Dombova ore twelve chip and channel samples have been analysed by KRUPP (1956), indicating the average iron content about 40 °/o. The average manganese contents for Melka Sedi iz 8,6 °/o and for Dombova 3,8 %». Phosphorus and sulphur range about 0,03 % and silica between 6 and 17 °/o. Several chip samples from different localities were analysed also in the Chemical laboratory of the Ministry of mines. The samples did not represent the average of the existing ore but rather relatively rich ore was taken. The results are shown in Table 4 (in percent): Table 4 4. tabela Locality Fe Mn Si02 ai2o3 Remarque Ilche 37,9 0,3 36,0 4,7 Siliceous ore Kurkure 45,0 1,64 20,0 3,15 Rich compact ore Aebdcha I 45,6 tr. 21,9 1,0 Siliceous breccious ore Aebicha II 34,8 0,1 41,0 0,0 Unclean breccious ore Sunaro 58,8 0,3 3,5 0,0 Clean compact ore Sombo 7,7 44,5 5,4 2,7 Rich manganese ore The microscopic examination of polished sections of ore specimens reveals the porous texture of limonitic ore composed of goethite prevailingly. The admixtures of impurities are often (PI. Ill, Fig. 1.). Psilo- melane occurs intimately intergrown with iron oxide but also in form of fine banding. Microscopic examination of the country rock reveals no mafic pheno-crysts in hollocrystalline porphyritic rock. Minute mafic components are disseminated in the matrix only. Decomposition begins in the matrix which get to be impregnated by yellowish pigment. The limonitic products fill up also the cleavages in sanidine phenocrysts, which get to change to products of kaolinization. Origin. Genetically the accumulation of iron and manganese can be explained through principles of supergene mineralogy of both elements. The mineralization is the result of chemical weathering of the country rock. Iron and manganese have been leached out of mafic minerals in the fine-grained matrix and precipitated more of less in situ, having accumulated in residuals and different openings in the rock where iron and manganese-bearing solutions have penetrated. Silica, alkalies and alkaline earths have been removed in solution and carried away. There is no doubt on the descending origin of the solutions. Also the morphology and the superficial character of the occurrences reveal a secondary enrichment only. Iron and manganese might have originated partly perhaps also from more basic rocks the presence of which is indicated in the area. However, the percentage of iron and manganese in acid rocks is low. Economically important iron ores of this genetical type are normally bound to more basic rocks. Reserves. Regarding the reserves Melka Sedi and Dombova deserve limited attention only. At both localities the quantity of useful compact ore does not exceed 20 °/o of the volume of the layers of altered ochreous decomposed rocks prevailingly. Hence the measured reserves of compact ore have been calculated to 65 000 tons for Melka Sedi and 12 000 tons for Dombova, having an average of about 40 % of iron and several percents of manganese. The additional inferred tonnages could be estimated to 25 000 tons only. From the point of view of smelting industry the reserves as indicated above have a very limited significance. An additional unfavourable factor regarding the mining is high compact ore — to — waste ratio, ranging about 1: 5. For all other localities the conclusion is due, that no reserves of economic importance were detected and can also not be expected. Taking into consideration also the transportation difficulties the reserves of Mai Gudo have very small economic importance for the time being. E n t o t o Entoto hill several kilometers north of Addis Ababa is known for a long time to yield iron ore. Old trenches and overgrown pits give evidence of former mining activity. Small isolate lenses and veinlike accumulations of hard limonitic ore are exploited in very reduced scale presently to meet local requirement of the Akaki smelting factory. The ore is used as extra-charge to the scrap iron. PL I, Fig. 1. Koree ore; — oil immersion, 600 X. Martitized magnetite (m), limonite (1) in cracks and small grains of sulphide (s) [. tab., 1. si. Ruda Korree; — oljna imerz., 600 X. Martrtiziran magnetit (m) z limonitom (1) v razpokah in drobnimi zrni sulfida (s) PI. I, Fig. 2. Dongollo basso ore; -— oil immersion, 135 X. Granoblaslic agregate of partly martitized magnetite in quartz matrix I. tab., 2. si. Ruda Dongollo basso; — oljna imerz., 135 X. Granoblastičen agregat delno martitiziranega magnetita v osnovi kremena PI. II, Fig. 1. Gumhod ore; — oil immersion, 600 X. Martitized magnetite (m) with small grains of chalcopyrite (ch) and malachite (ml) II. tab., 1. si. Ruda Gumhod; — oljna imerz., 600 X. Martitiziran magnetit (m) z drobnimi zrni halkopirita (ch) ter malahitom (ml) PI. II., Fig. 2. Agametta lore; — thin section, 40 X. Skarn ore: magnetite (m), garnet (g), epidote (ep) and quartz (q) II. tab., 2. si. Ruda Agametta; — zbrusek, 40 X. Skarnova ruda: magnetit (m), granat (g), epidot (ep) in kremen (q) PL III., Fig. 1. Mai Gudo ore; — oil immersion, 135 X. Porous impure limonitic ore III. tab., 1. si. Ruda Mai Gudo; — oljna imerz., 135 X. Porozna nečista limonitna ruda PI. III., Fig. 2. Ghedem ore; — oil immersion, 135 X. Zonal texture of ore, consisting of alternating bands of iron oxide (g), manganese oxide (m), silica (s) and calcite (c) III. tab., 2. si. Ruda Ghedem; — oljna imerz., 135 X. Oanarno strukturirana ruda sestoji iz izmeničnih pasov železovega oxida (g), manganovega oxida (m), kremenice (s) in kalcita (c) PL IV., Fig. 1. Ghedem ore; — oil immersion, crossed nicols, 135 X. Fine-crystalline agregate of pyrolusite IV. tab., 1. si. Ruda Ghedem; — oljna imerz., navzkrižni nikioli, 135 X. Drobno kristalast agregat piroluzita PI. IV., Fig. 2. Enkafela ore; — oil immersion, 135 X. Psdlomelane (p) and needleshaped hollandite (h) IV. tab., 2. si. Ruda Enkafela; — oljna imerz., 135 X. Psilomelan (p) in iglicast holandit (h) The Entoto mountain is built up of trachytic-rhyolitic rocks prevailingly. The ore occurrences are known on the southern slope of St. Raquel church's hill. The rocks are altered and decomposed on the surface and residual soil is accumulated in thick cover locally. The limonitic ore is found as fillings of fractures and cracks in the weathered rocks or as small isolated inclusions in decomposed rock. The ore is compact, glassy limonite prevailingly but sometimes soft and banded ochreous parts can be found too. The width of "veins" is several decimeters at the maximum. The origin of the ore is due to the leaching of iron by rain water during the weathering of country rock. Other leached components were carried away but iron precipitated in fractures and other openings in the reek. The colloidal ferric hydroxide hardens subsequently into amorphous glassy limonite with more or less obviously banded texture. The estimation of reserves is difficult. The quantity, however, can be expected very small and no economic importance might be attributed to the locality for the time being. On the other hand an accurate search of the whole mountainous complex would possibly reveal several new ore concentrations, however, of limited dimensions. The reserves of inferred ore can be estimated not exceeding several thousands of tons only. Nevertheless, the tranportation situation of this area is favourable and a smelter is near. Aira — Yubdo In the Aira-Yubdo area in Wollega volcanic Trap series overlays the pre-Cambrian metamorphic rocks. The volcanic cover is relatively thin and reduced partly only to the tops of the hills. The rocks are largely composed of olivine-basalt. Along the border of the Trap capping the presence of thin layers of ferriferous rocks of oolitic and spongy texture is evident on many places in the volcanics' marginal zone. Near Aira Mission the ferriferous rocks are composed of quartz sandstone and conglomerate witch limonitic cement. At the magnetite occurrence near Yubdo an oolitic limonitic layer can be observed in the basis of the basaltic cover overlying the metamorphic schists. Genetically the mineralization is a residual concentration of supergene iron oxides. The pre-Trapean residue, having resulted from the weathering of the basemnt rocks, was hardened by limonitic cement. The iron was dissolved by meteoric waters out of the basaltic rocks during the decomposition. The solutions percolated down and infiltrated the underlying residuals or other clastic rocks, having found a favourable place for the precipitation and deposition of dissolved minerals, and transforming them in oolitic and spongy ferruginous rocks. It is obvious that silica was leached and transported too due to the ferric-siliceous character of the existing ore. In this way also the long discussed "birbirite", a special spongy ferric-siliceous rock known from Yubdo platinum deposit, might be explained as limonitized and silicified former lateritic crust of ultrabasic rocks which, however, contain platinum too. An additionnal proof for 30 — Geologija St. 9 465 this explanation is the fact that "birbirite" can be found prevailingly along the western border of ultrabasic mass where it is still more or less in contact with basaltic cover. Sands and gravel near Aira Mission may have originated as young lacustrine sediments deposited before the extrusions took place. Porous clastic sediments were cemented subsequently by ferric oxides transported in solutions from the overlying volcanic rocks (Ha mrl a, 1963). The observed phenomenon of iron accumulation in the marginal zone along the volcanic capping occurs surely also on other places, where the geological conditions are favourable. The residual limonitic concentrations occurring in this way may be of theoretical interest only. At least in the Aira-Yubdo area the conditions as observed do not allow any hope for depositions of commercial value. Ferruginous siliceous rocks as sourcc of iron H a m a s e n General. The large occurrences of low-grade iron ore of residual type exist in Eritrea in the waste area south of Asmara, known by regional names Hamasen and Serae. Also there the natives smelted the ore to prepare the utensils and weapons. There is some descriptive information about the deposits of "nodular limonite" scattered in the waste area south of Asmara and also on other places in Tigre province. Dainelli (1943) described the phenomenon and later Us oni (1952) gave detailed information on the results of explorations carried out particularly during 1930/31. According to the Italian investigator Tis si the ore might extend on a large surface, and the thicknesses of layer are reported between 0,15 m and 0,6 m only. Geologically this part of Eritrean high plateau is built up by schistose rocks of pre-Cambrian age overlain by volcanic capping. The pre-Cambrian surface was erroded to a peneplain before the Triassic transgression took place. The subsequent denudation removed the greatest part of the uncomformably overlying Triassic and Jurassic sediments before the Tertiary volcanic cover spread over the weathered surface of the basement complex. The pre-Cambrian rocks of this area are predominantly phyllites, chlorite-schist and sericite-mica-schist streaking generally NNE—SSW, and containing gold-bearing quartz reefs. Granite bosses crop out at several places. The volcanics are built up by basalts, trachytes and rhyolites. Description. The concentration of iron oxides is connected to the zone of alteration on the old levelled surface of the schistose pre-Cambrian rocks. The reddish layers of ferriferous rocks are to be seen everywhere, where the errosion removed or cut the basaltic covering. The largest areas of exposed reddish ferriferous rocks extend in the surroundings of Mariam Sambel just westwards of the new airport of Fig. 13. Scattered pebbles of low-grade iron ore at Mariam Sambel SI. 13. Razmetani kosi nizkoprocentne železove rude pri Mariam Sambel Asmara (Fig. 13.), and westwards of Schicceti on the Asmara-Adi Ugri road. There are many additional more or less exposed occurrences along the whole margin of volcanic capping, and isolated islands occur on the basement where the volcanic cover was already removed. The approximate situation of the iron-bearing localities is given in the enclosed sketch (Fig. 14.). At Mariam Sambel low-grade iron ore can be found on a surface of about 3 sq. km. It is compact with a nodular and breccious appearance. The thickness of existing layer is difficult to estimate but it is thought to reach several meters at maximum. The limonitic-hematitic ore is low-grade by appearance and should contain a relatively great percentage of silica. Near Schicceti between the highway and the river Mareb there are large surfaces covered by reddish ferruginous products confined to the contact zone between the basement complex and overlying volcanics. The oxidized and secondary enriched ferruginous zone shows an obvious schistosity and represents the upper weathered part of the basement rocks, consisting locally of ferruginous and other schists (Fig. 15.). Irregular or lenslike inclusions of white siliceous staff are not seldom and might result from the precipitation of leached silica. The highest part of the secondary enriched zone is a breccious brownish-reddish rock of nodular and spongy appearance, similar to ferruginous concentrations observed by the author in Wollega and described above. Fig. 14. Provisional geological sketch map of Hamasen. (After L. Usoni) SI. 14. Približna geološka skica Hamasena. (Po L. U s o n i j u) There are many other localities in this region where the occurrences of iron oxides appear in the altered weathering zone immediately on the surface of crystalline basement rocks. In general, the ore appears mostly unclean, breccious and schistose textured, cemented with reddish cement. It consists of weathered rock and iron oxides and hydroxides. The passages from ferriferous concentrations to the schistose basement rocks can be observed especially in the lowest part of the layer. Fig. 15. Schistose low-grade iron ore with quartz inclusions near Schicceti SI. 15. Sbrilava nizkoprocentna železiova ruda z vključki kremena blizu Schicceti j a Analyses. As to the percentage of iron the low-grade ore contains there are large variations estimated visually to range between 5 and 6 °/o but averaging rather low. For the time being the data of several chemical analyses given by U s o n i (1952) are available only. The iron contents is reported to vary between 30 and 56 % and silica 13 to 18 %>, averaging accordingly to 40 % of iron and 16 % of silica. The contents of other admixtures like phosphorus and sulphur is very low. These values can be accepted as a rough orientation only because no garanty exists on the correctness and precision of sampling and analysing performed. The visual estimation of an average percentage of metal in the ore is much lower. It is possible, however, that parts in the mineralized zone exist which might yield a higher average in iron. Origin. The supergene enrichment of iron is due to the weathering of the pre-Cambrian basement rocks in the period of emersion before the lawa flows dispersed over the peneplained and levelled surface. According to Mohr (1961) the age of weathering and decomposition can be dated as belonging to the Portlandien-Eocene interval. The basement rocks were oxidated and leached during that interval and the rain-water removed different constituents of the rocks other than iron which remained and enriched in situ. The aspect of the mineralized layers is thus an argilaceous and breccious. A part of supergene iron could be leached also out of the overlying basaltic capping and after percolating the fractures and cracks it precipitated and accumulated in the upper part of the weathered and decomposed basement rock. Reserves. According Us oni (1952) Tis si examined the deposits in 1931 by 219 shallow pits and trenches. He estimated the total reserve of low-grade iron ore might be about 15 million tons, a half of this tonnage being situated in the immediate surroundings of Asmara. Supposing the continuity of the ferriferous deposit under the volcanics, T i s s i estimated the inferred reserves to 200 million tons. Nothing more definite is possible to say about the reserves existing in this area as well as the quantity of ore with a satisfactory chemical composition for the time being. It could be expected that several tens of million tons of ore might be potentially important regarding the quality as well as other factors influencing the eventual exploitation. Anyhow, the deposits must be regarded as a potential second- or third-order source due to the low contents of metal. Regarding the transportation facilities their situation is good. The future of these deposits might be perhaps in blending with high-grade ores. To asses the existing ore detailed exploration is necessary. It is being carried out by the Ministry of mines for the time being in order to detect richer and thicker parts of the layers. Tigre Many explorers observed the ferriferous lateritic formations in Tigre province and reported upon the existence of iron deposits. An old primitive exploitation on a small scale as well as smelting for local requirements is known in different parts of the province. Quite exhaustive description of these and Eritrean deposits is summarized by Dainelli (1943). U s o n i gives some general information concerning the most important localities between Adua, Axum and Enticcio (Us oni, 1952). The iron occurrences are reported to be "ferriferous laterites" similar to those in Eritrea, and connected to the basement rocks as well as to the Mesozoic formations of Adigrat and Upper sandstones. The interesting appearance of nodular and pisolitic limonite concentrations is known to exist at many of those places where clastic sandstones crop out. M e r 1 a and M i n u c c i give some detail on mineralization indicating that the prevailing limonitic "lateritic crust" has a thickness of 5 to 6 m at maximum, but the weathered zone of the sandstones is much thicker (M e r 1 a , Mi n u c c i, 1938). According to Villaminar the grade of metal averages about 45 °/o (Murdock, 1960). As to the genesis of iron accumulation Mer la and Minucci considered it as a result of lateritization of sandstones during the pene-plaination which preceeded the Trappean eruptions (Merla, Minucci, 1938). The ferruginous cement of sandstones might be of primary authigene origin. On the other hand, Dainelli considered the presence of the opaline-limonitic sediments as to have been transported in the Uper Jurassic or Cretaceous period from the lateritized emerged basement rocks and sedimented in the sea (Dainelli, 1943). According to Mohr (1961) there is obvious evidence of the lateritic weathering on the top of Upper sandstone. The lateritic crust found in Eritrea upon the basement complex passes further south into the sandstone formations. The alteration takes the form of a limonitic enrichment of the topmost strata to a depth of some ten meters. It is probable that the enrichment of iron might be locally sufficient to form an economic iron-ore deposit. No figures for the reserves are known, but it can be expected that perhaps several million tons of low-grade ore might be available. Other residual occurrences The phenomenon of iron concentration as described above for different more known localities occurs in the whole region of the Ethiopian plateau where similar petrographic, morphologic and climatic conditions exist being in general convenient for leaching and transportation of iron'and its accumulation either in residual lateritic soil or other favourable environment. There is some information on local iron ore occurrences at different localities of Ethiopia, but the details are rather limited and up to now no one of them deserved larger interest regarding the economic importance. Dainelli (1943) gives an overlook of find-spots of ore and these localities are indicated or described many times in several other reports. Residual deposits are known from Beghemder west of Tana lake and north of Gondar as well as near the town itself. The occurrences are reported from Gojjam some 100 km north of Debra Marcos, and from Ankober in Shoa. A small lateritic-infiltration type occurrence is reported to exist near Yavello in Sidamo province (M u r d o c k , 1960). To the same type belong probably the occurrences reported to exist at Maji and Gurrafarda in Kaffa province. 4. Hydrothermal type Ghedem General. The sole more important known deposit of hydrothermal origin is situated some 7 km southeast of Massaua, occupying the extreme northern part of the Ghedem mountain. The deposit was visited and explored many times in the past as described by Us on i (1952), who summarized all what was knovn about it. The main exploration and exploitation of the ore took place immediately before the War II. Several trenches, pits and bore-holes were executed and a limited tonnage of ore was exported to Italy. There was no certainity about the origin of this iron and also manganese accumulation and Mohr even in 1961 ranged the deposit as a probably pre-Cambian sedimentary one. In 1963 preliminary prospection and studies were carried out by the Ministry of mines (H a m r 1 a , 1963). Early in 1964 the deposit was searched geologically and geophysically by the Yugoslav RUDIS company on behalf of the Ministry of mines in order to establish definitely its eventual economic signification. The mineralizations are located on a hill confined on three sides by dislocations and surrounded by alluvial sands and gravels. The prevailing direction of the faults is about 30° and the dip is more or less vertical but dislocations run also about 150°. Here and there along the borders of the hill the slickenside fault surfaces can be clearly seen with traces of oblique movements. The faults are accompanied by tectonic breccias. The main ore bodies are bound to these dislocation (Fig. 16.). The area is built by metamorphic crystalline rocks. Micaceous and gneissic schistose rocks prevail, dipping generally 75° to 80° west. Pegma-titic veins and dikes in various directions are often. Greenish porphyry rocks appear at some parts of the hill. Gray-black crystalline carbonate rock appears along the borders of the hill following the main tectonic directions. It forms elongated ridges like dikes on the hill and it fills the cracks and fissures in pegmatites and other rocks, being directly Fig. 16. Ore body No. 3 along the torrent Ghedem SI. 16. Rudno telo št. 3 vzdolž hudournika Ghedem Fig. 17. Provisional geological sketch map of Ghedem deposit SI. 17. Približna geološka skica nahajališča Ghedem connected with iron and manganese mineralization (Fig. 17.). Carbonate gangue alternate with iron and manganese oxides in bands, indicating in this way the obvious genetic connection. Description. The main ore bodies appear allong the borders of the hill in form of lenslike outcrops, having an average lenght of several ten meters and thickness of several meters only. The best exposed outcrops are situated along the torrent Ghedem due to its errosive activity. Many smaller ore outcrops are occurring in the southern part of the hill, accompanied by calcareous gangue which includes more or less of metal oxides as incrustations or inclusions. Iron ore is limonite prevailingly, having a porous and spongy texture. The breccious ore is composed of particles of country rock, cemented by iron and manganese oxides. Manganese ore appears generally fine-banded mammillary or as crusts, being intimately mixed and intergrown with iron oxide. The ore is generally composed of both iron and manganese oxides. The main ore body, a part of which is already removed by excavations, shows visible dimensions 75 m by 15 m by 5 m approximately. The porous limonitic ore seems to be crushed and mylonitized and subsequently cemented again with iron oxides. In the vicinity of the ore body many thin veins of ore intersect the adjacent country rocks. The visible dimensions of the other ore outcrops are smaller. The ore is in general more breccious and impure with increased contents of manganese. The breccious texture gives obvious evidence of a tectonically effected mineralized zone. Blackish manganiferous limestone everywhere accompanies the ore. The separation of the ore outcrops on the western side of the hill along the torrent Ghedem was thought to be due to errosion, but this hope was disproved by RUDIS' survey in 1964. On the southern part of the hill several mineralized limonitic zones and small ore outcrops can be observed at many places. No traces of exploitation can be seen there. On the north-eastern border of the hill there are two outcrops of ore which have been mined in the past. The ore is breccious and manganese oxides prevail. Also this border is obviously tectonically effected and fragments of ore can be found intermingled with slope-rubble. Analyses. All transitions between calcareous waste and rich either iron or manganese ore can be observed in the field. The results of analyses of several chip samples of ore and of two average samples of ore shipped in 1940 to Italy are given by Us oni (1952). The chemical composition of Ghedem ore might result accordingly as follows (in percent): Fe about 54 S 0,055 to 0,13 SiO., about 12 P 0,027 to 0,04 Mn" 0,2 to 0,45 This quality, however, can not be expected as an average one because the ore from diverse outcrops differs in great extent due to the varying mineralogical composition and admixtures of impurities. The iron ore — to — manganese ore ratio might be in general about 18: 1 relating to the Italian sources (U s o n i, 1952). No new chemical analyses of ore are available presently. The carbonate gangue was chemically examined only in order to clear its composition which is the following (in percent): CaC03 94,0 SiO, 0,3 Fe„03 1,86 S 0,00 ALA 1,64 Mg 0,00 MnO 3,1 The admixtures of manganese oxides cause the black colour of the carbonate rock. Besides the calcite the elongate shaped crystals would point to aragonite. Microscopic examination of the ore reveals the prevailing concentric texture of oxidic minerals in form of fine curved bands and zones (PI. Ill, Fig. 2.). Radial crystallization is common, and the fibrous radially arranged agregates with long axes normal to the bands show continuous transition through bands and zones with fine needle-shaped free surfaces. Goethite is the prevailing iron mineral. Bandlike ochreous inclusions seems to be replaced by goethite. Manganese oxides are represented by fine-grained psilomelane and fine fibrous pyrolusite (PI. IV, Fig. 1.). Some yellow bands might belong to hollandite. Small flaky inclusions of pyrolusite are found in goethite. Silica occurs in form of irregular cryptocrystalline masses and alternates in bands with other oxides. It contains more or less fine dispersed oxides and forms a jasper-like cherty rock. Calcite is present in relatively big crystals and never as fine banding. Small irregular inclusions of manganese oxides are always present in it. More "generations" of iron and manganese oxides are evident. Origin. The accumulations of iron and manganese oxides, accompanied by gell quartz and carbonate gangue, have originated from thermal solutions. The mineralization might be classified as epithermal or rather hot-spring deposition and was caused by a relative young thermal cycle. The deposition took place as filling of holes and cavities along the dislocations, cementing the technically crushed zones under the formation of breccious ore. There is no doubt of an ascendent character of the solutions which must have been loaded with C02. About the origin of these acid solutions nothing can be said with certainty. They were very probably bound to the young (Pliocene or Pleistocene) volcanic activity in the region, being either of juvenile or surface provenience as ascending heated meteoric waters. The alternating bands of different oxides were caused by variations of physico-chemical conditions during the precipitation. The fine banding is, however, normally the proof of deposition in a colloidal state. The zonal structures observed develop mostly by minerals of supergene origin which are deposited as alteration products from cold aqueous solutions. Such textures, however, are found also in hypogene minerals and iron and manganese oxides are known to originate also as hydrothermal low-temperature products. As to the mechanism of precipitation the constituents might have been transported in molecular solutions as bicarbonates, and after oxidation transformed partly to more stable colloidal state and precipitated as gels. Carbonate crystallized probably from bicarbonate solution. Other components precipitated subsequently as gels and acquired later more or less expressed crystallinity. It can be assumed that the acid solutions percolated the deeper parts of the earth's crust, having leached iron, manganese, silica and calcium out of different rocks of metamorphic basement series. Another possibility is the solutions are derivatives of a magmatic source. Reserves. According to U s o n i the reserves of ore were estimated in the years before the War II by T a z z e r who calculated the visible part to 80 000 tons, the probable one to 32 000 tons, and the possible one to 540 000 tons. M i n u c c i estimated the visible tonnage to 85 000 tons, and the possible one to 265 000 tons (U s o n i, 1952). On the basis of recalculation of reserves in the field the conclusion can be made that the visible part of the outcrops amounts to about 36 000 tons. Some additional 40 000 tons of possible ore may exist in the immediate prolongation of the outcrops to the depth. According to the type and form of the deposit some hundreds of thousand tons might be additionally considered as inferred possible tonnage (Ha mrl a, 1963). These figures practically coincide with those given by Italians. The deposit has to be classified accordingly as a very small one. Altogether about 30 000 tons of ore have been excavated only (Us oni, 1952). The RUDI S' estimate of the total quantity of ore is about 650 000 tons, and it should be considered as possible reserve only. The prospection of the surroundings of Ghedem, carried out in the season 1963 by the Ministry of mines, did not find any additional mineralizations of the same type. Chilachikin According to KRUPP's report (1964) the Chilachikin iron ore occurrence is situated near the Asmara-Gondar road, about 30 km southeast of Enda Selassie and some 270 km from Asmara. The area is composed of pre-Cambrian phyllites and sericite-schists, traversed by numerous young quartz veins which in a few cases show marginal iron mineralizations. Mesosoic sandstones form isolate cappings on the tops of hills and mountains. No information is available of any former investigation in this area. KRUPP executed several trenches which exposed quartz veins in schistose rocks. The thicknesses of the veins are between 0,1 m and 0,5 m, but in many cases under 0,1 m. The 1,5 m thick quartz vein is marginally mineralized with coarse-grained hematite, the width of mineralized band being 5 cm or about 5 % of volume only. The iron mineral is specular hematite. Its connection to quartz veins can be interpreted as apparently katathermal derivative of a magmatic source. Veins of this kind are rarely of economic importance, and also this occurrence is interesting from a mineralogical point of view only. As much as it is known until now there are very few iron ore occurences in the country formed by ascending solutions. U s o n i guesses some iron ores connected to quartz gangue at Agame region could be of hydrothermal origin (U s o n i, 1952). There are no other data available on the existence of other hydrothermal iron ore occurrences in Ethiopia and this genetical type is unimportant as potential source of iron ore. 5. Magmatic type There are no precise data available refering to the iron ore occurrences of magmatic origin. The suspection that iron ores of magmatic origin might exist in the country is due to a sample of granular magnetitic ore gathered during the prospecting campaign in 1963 in the area north of Nejo in Wollega (Hamrla, 1963). The microscopic examination of ore specimen revealed a granular intergrowth of allotriomorphic magnetite and ilmenite with an idio-morphic axial mineral, belonging probably to the group of orthopyroxenes, and amounting to about 50% by volume. Magnetite shows the initial martitization. The composition of ore sample is 39 % of iron, 5,9 % of titanium beside silica and a small percentage of magnesia. This ore might be a product of magmatic crystallization differentiation. No other data are available for the time being. The find-spot was not yet examined and the geologic feature of the occurrence is not yet known. MANGANESE 1. Residual concentration type All known residual occurrences of manganese are bound to the concentrations of supergene iron oxides described above. It is well known that manganese is very similar in behaviour of transportation and precipitation to iron. In supergene deposits they are normally both found together. Manganese can be easier removed in solution in comparison with iron, but it does not precipitate as easy as iron. The manganese hydroxides are normally deposited as gels from colloidal solutions and solidify as psilomelane. They undergo subsequently further dehydration and crystallize as pyrolusite which acquires more or less expressed crystal-linity and exhibits radial texture. The accumulations of manganese oxides in described residual iron deposits have no economic importance. In Mai Gudo area manganese oxides are closestly connected to iron oxides as inclusions or intergrowings. Local concentration of manganese ore was found at the locality Sombo in form of several centimeters thick lenticular ore seam, the composition of which is given in Table 4. Mineralogically, psilomelane in colloform banding and zoning prevails and earthy wad is common too. In general, the contents of manganese in Mai Gudo iron ore ranges from 4 to 12%. The conditions for formation of richer and larger depositions were not favourable in this area, because the content of manganese in trachytic-rhyolitic rocks is to small to give rise to more important residual manganese concentrations. Similar small and scarce accumulations of supergene manganese minerals are known from different other places, and their formation is due to the weathering phenomenon of volcanic rocks. 2. Hydrothermal type The only occurrence of manganese ore of hydrothermal origin is known at Ghedem. The geological side of the deposit is described above. Manganese oxides in form of psilomelane and pyrolusite occour in general closestly connected to iron oxides, forming colloform textured ore of alternating bands and zones or as incrustations within breccias and carbonate waste. Manganese oxides are fine-crystalline prevailingly (PI. IV, Fig. 1.). The black colour of the accompanying manganiferous calcstone is due to the fine admixtures of manganese oxides which are displaced in calcite crystals following the rhomboeder directions, but also among calcite grains. The prevailing manganese ore occurs along the north-eastern border of the hill, as evidenced in several outcrops or trenches. The contents of manganese in this ore might be about 40 °/o. The rich manganese ore was exploited separately in the past, and there is still a quantity of about 800 tons stored in piles near the working places for the time being. The mineralization can be explained by a young thermal cycle, having originated either from leaching of deep-lying rocks or from solutions of magmatic origin. There are outcrops of more of less manganiferous ore or ferruginous manganese ore or even pure manganese ore. This very pronounced and quick change in the composition of ore regarding the contents of oxides as well as carbonate gangue could be explained by very unstable physico-chemical conditions of deposit's formation. The reserves of manganese ore from Ghedem can be estimated to about 4000 tons of visible and probable ore. The inferred tonnage could be expected to reach some tens of thousand tons at maximum. 3. Sedimentary type Enkafela General. Enkafela is the only known manganese ore deposit of sedimentary origin. The locality is situated about 20 km southwest of Dallol on the border of the Salt plain in the Danakil depression, and was discovered incidentally several years ago. A prospection licence and lease for exploitation was given in 1955 covering an area 300 m by 350 m only, and in 1958 primitive mining started under a private licence. The ore is transported by truck to the port of Mersa Fatma on the Red sea coast, and exported via Massaua to USA. The production is small and altogether not more than 40 000 tons of ore have been exploited and shipped to Massaua till the end of 1963. The geology of the Salt plain depression is characterized by an early Pliocene sea ingression which deposited during Plio-Pleistocene marine beds composed of conglomerates, sands, clays and evaporites. All around the Salt plain conglomeratic and gypseous sediments occur which were formed in the shallow sea along the former coastline. Along the whole western margin of the Salt plain thick layers of terrassed pluvial torren- Fig. 18. Provisional geological sketch map of the northern Salt plain depression. (After various sources) SI. 18. Približna geološka skica severnega dela depresije »Salt plain«. (Po raznih virih) tial gravel rest unconformably on marine sediments which are well exposed only in young wadi-cut valleys. In such a valley of the Handeda river the manganese ore became erroded and the layer exposed. The manganese ore is interstratified in the clastic marine succession, and its sedimentary nature is evident. The mountains bordering the Enkafela area to the west are composed of volcanics, meanwhile to the east huge deposition of piedmont gravels form the passage to the Salt plain (Fig. 18.). Description. The Enkafela mining area covers a surface of about 250 m by 300 m for the time being. Several lenslike ore outcrops can be observed in the wadis. The layer exploited has a maximal thickness of 1,4 m in center and decreases to 0,1 m towards margins. The total volume of the known ore might be thus not more than 10 000 cubic meters only. Marginal passages of ore to the waste can be observed. The greyish black cavernous ore is pure and occurs as botryoidal and spongy mass composed of hard oxides. A very fine crystalline texture can be seen along the cavities. The ore bed is overlain by thin irregular ferriferous breccious layer. The footwall of the ore body consists of coarse clastic sediments containing sands and gravels, and cemented in the upper part with manganese oxides. The hanging wall consists of tuffic aglomerates with corals and other marine fossils. Fig. 19. Interstratified layer of manganese ore at Enkafela SI. 19. Med plasti vključen sloj manganove rude v Enkafela The following succession of the ore-bearing marine sediments was observed in the eastern part of the open pit (Fig. 19.), from bottom up: 0,5 to 0,8 m Middle-grained sandy breccia, including small nodules and vertical thin veinlets of manganese oxides; 0,1 to 1 m Coarse gravel and sand, cemented with manganese oxides (pebbles and grains of volcanic origin prevailingly); 0,5 to 0,8 m Banded manganiferous impure sandy bed of loose consistence; 0.5 to 0,9 m Compact manganese ore; 5 to 6 m Tuffic aglomerates with corals and other marine fossils; 8 to 10 m Marly sandstones, well banded; 10 to 15 m Torrential gravel. Another outcrop of manganese ore was found at the locality Ashley some 7 km north of Enkafela. Several thin earthy layers of manganese ore can be observed, having a thickness not more than 0,3 m totally. The geological environment corresponds entirely to that described for Enkafela. Thin-bedded marine sediments prevail, being covered by a thick layer of torrential gravel. Analyses. The average chemical composition of the Enkafela ore which was shipped from Massaua to USA between 1960 and 1964 is as follows* (in percent): Mn (dry basis) . . . . 51,26 Moisture .... . . 0,68 Si02...... . . 1,81 A120........ . . 0,80 Fe20,...... . . 1,50 BaO...... . . 7,70 S....... . . 0,029 P....... . . 0,021 Pb....... . . 0,000 Cu....... . . 0,000 As....... . . traces The quality of ore is good although the admixture of barium is significant. Under the microscope manganese minerals can be seen only. The ore show mild zoning. Microcrystalline agregate of psilomelane in mixture with some pyrolusite prevails. Hollandite occurs too and yellow relatively bigger prismatic crystals are concentrated in thin zones (PI. IV, Fig. 2.). Origin. The deposit of relatively recent geologic age is of sedimentary origin and was formed in the shallow sea-shore zone rich in oxigen. The manganese might originate from the decomposition of different volcanic rocks in the western hinterland of the Salt plain, and was transported by flowing waters into the littoral sea. It precipitated as manganese hydroxide and was diagenetically transformed to psilo-melane-pyrolusite compounds. Iron oxides are normally admixtured to the primary oxidic ore and they are found in Enkafela immediately on the top of the manganese bed. It is believed for the time being that in sedimentary deposits manganese was precipitated directly from sea-water by the activity of microorganisms. Another possibility about the source of manganese could be the connection with hot-spring volcanic activity of that time. More detailed investigation of facial environment as well as the mechanism of precipitation of ore could provide useful hints for the eventual further finding of new accumulations in the vicinity. Reserves. The total amount of ore which was yielded from the deposit hitherto ranges not more than several tens of thousand tons totally. At the end of 1963 the still existing visible reserves have been estimated not more than about 5000 tons only. Due to the sedimentary ♦Personal communication by Mr. L. Zingoni (Technical Officer of the Mining Office in Asmara). 31 — Geologija št. 9 481 character of the deposition in the former littoral zone, the further economic findings in the immediate vicinity are possible. The known and exploited lenslike ore bodies pass laterally to the sterile or low-grade mineralized clastic rocks. In the case the source of manganese were the volcanic or other rocks of the hinterland, the western border of the Salt plain's sedimentation basin could be a large geological environment which might have favorized the deposition of manganese, and the lateral persistency of the ore-bearing horizon is probable. This assumption is supported by the appearance of the ore at Ashley. Hence, it would be advisable to explore the marginal part of the western piedmont area of the Salt plain depression in order to find out the eventual new manganese ore concentrations. IRON AND MANGANESE DEPOSITS IN THE NEIGHBOURING COUNTRIES For the reason of comparison, and following the available sources, the iron and manganese deposits of the neighbouring East African countries are described in the shortest way. There are several iron deposits existing in Sudan. The country's geological setting is similar to that of Ethiopia, being composed of pre-Cambrian rocks and Mesozoic and younger sediments. In the Red-Sea zone north of Port Sudan the Sufaya and Fodikwan deposists consist of massive magnetite-hematite ore. The ore bodies extend in conformity with the folliation of the metamorphic rocks dipping steeply east. The layered deposits might seem to be genetically similar to those of Eritrea, or might even belong to the same ore-bearing zone which extend between Falcat and Agametta. More accurate data point to the genetic interpretation of deposits by magmatic differentiation.* Accordingly, the ore bodies originated as ore injections bound to diorite-lamprophyres at Sufaya and porphyrites at Fodikwan. The reserves of high-grade ore are reported to range over 10 million tons for each of the deposits, and there is a large quantity of low-grade ore in addition. The position close to the Red-Sea coast is favourable, and plans have been prepared to exploit the ore at a rate of several hundreds of thousand tons yearly. At Abu Tulu in Northern Sudan a similar deposit consists of high-grade magnetite-hematite ore. It extends in the nort-eastern strike of the metamorphic complex. The reserves are reported to amount to 36 million tons. A deposit of resigual type' exists at Kutum in Western Sudan. It might be bound to the process of weathering of Nubian sandstone. The ore is concretionary hematite and the reserves total 2 million tons. A small deposit of probable hydrothermal origin at Fadlab northeast of Khartoum originated as replacement of marbles by hematite. The reserves are several hundreds of tons only. * Personal communication by Mr. M. Dolenc, Chief geologist of the Geological Survey , peska pa je 20 do 62 %>. Tudi po litološki sestavi se pliocenski prod močno razlikuje od pleisto-censkega. Pleistocenski prod vsebuje poleg kremenovih tudi prodnike amfibolita, tonalita, gnajsa in redko apnenca, medtem ko v pliocenskem produ prevladujejo dobro zaobljeni drobni kremenovi prodniki. Tako sestavo pliocenskega proda je mogoče razložiti z večjo transportno razdaljo v pliocenu, medtem ko je bila ta razdalja v pleistocenu zaradi ledenikov mnogo krajša in so se poleg prodnikov kremena ohranili tudi prodniki manj odpornih metamorfnih hribin. Med vrtanjem smo pliocenske plasti raziskali tudi po standardni metodi penetracije. V pleistocenskem produ te raziskave niso uspele zaradi debelih oblic, ki prevladujejo v produ. V pliocenskem produ, pesku in peščeni glini so penetracijski preizkusi povečini uspeli in so pokazali, da so pliocenske plasti dobro konsolidirane; penetracijska konica je prodrla v globino 1 čevlja (30,5 cm) šele po 100 do 250 udarcih. Zaradi velike razlike hidrostatičnih pritiskov v vrtini in zunaj obložne kolone je pleistocenski prod ob izvlačenju jedrne cevi prodiral navzgor v obložno kolono. Med vrtanjem v pliocenskem produ tega pojava ni bilo. V pleistocenskih plasteh je bilo treba obložno kolono zabiti do dna vrtine po vsakem izvlačenju jedrne cevi, ker so se sicer stene rušile. V pliocenskem produ pa je bilo možno vrtati brez cevitve do 10 m globoko. Ta pojav je nastal zato, ker je bil ob spodnjem koncu obložne kolone strujni pritisk v pleistocenskem produ večji od njegove prostorninske teže, zmanjšane za vzgon. V pliocenskem produ pa ta pojav ni možen, ker ima večjo prostorninsko težo in poleg tega določeno kohezijo. Raziskave vzorcev nekoliko sprijetega pliocenskega proda iz vodnjaka BV, so pokazale, da je njegova prostorninska teža pri naravni vlagi = 2,06 do 2,3 t/m3. Prostorninska teža pleistocenskega proda pa doseže največ 2,04 t/m3. Dopustna obremenitev pliocenskega proda v globini 2 m pod površino je po predpisih PTP 5 kp/cm2, v globini 37,5 m pod površino, pod temelji strojnice, je znatno večja. Temeljna tla bodo po izkopu gradbene jame razbremenjena za celotno težo izkopanega materiala. Razbremenitev bo dosegla vrednost 52,5 t/m2, računano po obrazcu 0z = 7 . h + (ys — y ). (1 — n). (z — h) o2 = normalna napetost v navpični smeri y„ = 2,7 t/ms (specifična teža trdne snovi) yw ~ 1 (specifična teža vode) z = 37,5 m (globina izkopa) n — 0,25 (poroznost) y = 2,025 t/m3 (povprečna suha prostorninska teža pleistocenskega in pliocenskega proda) h = 8 m (globina izkopa nad vodo) Izkop gradbene jame bo do globine 8 m v suhem peščenem produ, niže bo pod gladino podtalne vode. Ker je izkop z mehanizacijo mogoč le do določene globine, je projektant predvidel črpanje vode iz gradbene jame, da bi bil izkop na suhem. Temeljna tla bodo po izkopu gradbene jame razbremenjena in se bodo zato dvignila. Ker ni znan deformacijski modul E pliocenskega proda, ne moremo povsem točno izračunati, za koliko se bodo tla dvignila. Po podatkih laboratorija za mehaniko tal univerze v Ljubljani (K e r i n , 1965) bo dvig znašal 19,5 do 28 cm. Ko bo strojnica zgrajena, se bodo tla ponovno posedla. Posedanje bo manjše od dviga, ker je predvidena teža zgradbe manjša od teže izkopanega materiala. Del zgradbe s turbinama, obrnjen proti toku, je težji od nasprotnega dela, obrnjenega v smeri toka. Bolj obtežen del temeljnih tal se bo tudi bolj posedel, in sicer za 19 do 21 cm, medtem ko se bo manj obtežen del posedel za 16 do 19 cm. Razlika v posedanju je torej 3 do 5 cm. Vendar so te številke le približne, ker je bila pri izračunavanju privzeta za^ deformacijski modul E pliocenskega proda zelo nizka vrednost (670 kp/cm2). Zato bosta dejansko posedanje in razlika v posedanju obeh delov strojnice manjša. Med gradnjo bo potrebno opazovati posedanje strojnice, da bi preprečili morebitne okvare turbin po pričetku obratovanja elektrarne, ki bi nastale zaradi nagibanja strojnice. Hidrogeologija Za izračunanje dotoka vode v gradbeno jamo je bilo potrebno čim točneje ugotoviti vrednost koeficienta prepustnosti pleistocenskega in pliocenskega proda. V ta namen smo raziskali prepustnosti prodov laboratorijsko ter s črpalnimi poizkusi v vodnjakih in vrtinah. Za ta članek smo podrobneje vrednotili samo rezultate raziskav v pliocenskem produ, medtem ko bodo podatki o pleistocenskem produ obdelani v posebni razpravi. S poizkusnim črpanjem v vodnjaku BV2 je bilo ugotovljeno, da je srednja vrednost koeficienta prepustnosti k pleistocenskega proda 4 1 do 4.63.10-1 cm/sek (2. si.). Podatkov za vrednost koeficienta prepustnosti pliocenskega proda je bilo znatno več. 2e leta 1959 smo s črpalnim poizkusom v vrtini C., LEGENDA K 2. SLIKI ELPLA NATIONS TO FIG. 2 PIEZOMETER Z GLADINO VODNEGA HORIZONTA V PLIOCENSKEM PRODU P'EZOMETEP SHOWING THE WATER TABLE IN PLIOCENE GRAVEL J>t30 PIE20METER Z GLAOINO VODNEGA HORIZONTA V PLEISTOCENSKEM PRODU W PIEZOMETER SHOWING THE WATER TABLE IN PLEISTOCENE GRAVEL VODNJAK BVp TER VRTINA 2 GLADINAMA VODNIH HORIZONTOV q V PLEISTOCENSKEM (N PLIOCENSKEM PR00U WELL Bvj ANO ORlU HOLE SHOWING THE WATER TABLES IN PLEISTOCENE AND PLIOCENE GRAVELS ____________________________VOONEGA HORIZONTA V PLIOCENSKEM PRODU DNE 27.4.1964 CONTOURS OF THE GROUND WATER TABLE ON APRIL 27, 1964 ^ HIDROIZOHJPSE VODNEGA HORIZONTA V PLEISTOCENSKEM PRODU DNE 27.4.1964 •""* CONTOURS OF THE GROUND WATER TABLE ON APRIL 27,1964 . SMER TOKA POOTALNE VODE PLOW OlRECTlON OF THE GROUND WATER II II 5 10 15 20 m SI. 2. — Fig. 2 v Hajdošah ugotovili, da v pliocenski prodni plasti, izolirani v krovnini in talnini z glino, niha vrednost koeficienta prepustnosti med 5,05.10~2 in 5,14.10-3 cm/sek. Na območju strojnice v Zlatoličju smo prepustnost pliocenskega proda preizkusili s tlačenjem vode v vrtine Sa, S.,, S4, S:,, S,S7 in S„. Prepustnost smo v vrtinah raziskovali po odsekih 2 do 8 m, ker smo se morali ravnati po tehničnih možnostih zatesnitve vrtine z obturatorjem. V prodnih plasteh obturator ni povsod tesnil, zato smo ga morali pomikati navzgor in navzdol, dokler nismo dosegli zadovoljive tesnitve. Merili smo povečini le pri dveh različnih pritiskih; ko je pritisk vode narasel prek 5 kp/cm2, je voda pogosto predrla stene vrtine ob obturatorju, kar se je pokazalo v nenadnem padcu pritiska. Za izračunanje Darcyjevega koeficienta k po podatkih merjenja prepustnosti je mogoče upoštevati le pritiske na stene vrtine v merjenih odsekih, zato je bilo treba odšteti tlačne izgube, ki nastanejo pri pretakanju vode skozi drogovje, prišteti pa pritisk vodnega stebra od manometra do gladine podtalne vode. Vodne izgube pri raziskavah prepustnosti so nihale od 8,5 do 52 l/m/min pri pritiskih 3,5 do 4,5 kp/cm2 v določenih odsekih. Koeficient prepustnosti »k« smo izračunali po Dupuitovi enačbi za dotok vode iz horizonta pod pritiskom: R 0,36 6. Q.log- fe =--1 M.H M = dolžina raziskanega očlseka vrtine v m r r= polmer vrtine v m Q = vodne izgube med preizkusom VDP v m3/sek H — pritisk vode na stene vrtine, izražen v m vodnega stebra R = polmer vpliva v m 100 m. Izračunane vrednosti k so približne, ker dejanske razmere niso ustrezale v celoti pogojem enačbe, vendar so za oceno prepustnosti uporabne. Tako izračunane vrednosti koeficienta k nihajo od 3,76.10~4 do 3.10-3 cm/sek. V geomehanskem laboratoriju univerze v Ljubljani so' v permea-metru raziskali vzorce pliocenskega proda iz vodnjaka BV,, zbite na isto prostorninsko težo, kot je bila ugotovljena pri neporušenih vzorcih proda. Ugotovljeno je bilo, da niha koeficient prepustnosti k od 1,2.10-4 do 5,3.10-® cm/sek. Vse navedene raziskave so kazale, da je pliocenski prod vsaj stokrat manj prepusten kot pleistocenski prod. Da bi potrdili rezultate raziskav, so izkopali vodnjak BVj do kote 197,5 m, ki je bil perforiran v pliocenskem produ le od kote 206 m navzdol. Po podatkih poizkusnega črpanja je bil koeficient »k« pliocenskega, proda 3.10-2 cm/sek, kar je le desetkrat manj kot prepustnost pleistocenskega proda. SI. 3. Depresijska krivulja pri črpanju 1,8 m8/h iz vrtine v vodnjaku BV2 Fig. 3. Drawdown curve at discharge 1,8 m3/h from t.h drill hole located within the well BV2 Ti podatki so se močno razlikovali od prej ugotovljenih. Izražen je bil sum, da je voda dotekala v perforinani del vodnjaka ne samo iz pliocenskega proda, temveč ob stenah vodnjaka tudi iz zgornje, močno prepustne pleistocenske prodne plasti. Posebno pozornost so vzbudili podatki kemičnih analiz vode, ki je bila vzeta med črpanjem iz vodnjakov BVj in BV2. Po kemični sestavi sta bila oba vzorca vode skoraj enaka, čeprav je bil vodnjak BV2 perfori-ran v pleistocenskih plasteh, vodnjak BV\ pa le v pliocenskih plasteh. Trdota je bila pri obeh vzorcih 14,6° dH. V nasprotju z dobljenimi rezultati analiz smo pričakovali, da se bosta vodi razlikovali med seboj, ker je litološka sestava pleistocenskega in pliocenskega proda precej različna. Za projekt izkopa gradbene jame in gradnje strojnice je bilo treba poznati čim točnejšo vrednost koeficienta h pliocenskega proda. Zato je Geološki zavod po naročilu Dravskih elektrarn ponovno izvedel poizkusno črpanje v pliocenskem produ. V ta namen je leta 1964 izvrtal z dna vodnjaka BV.2 vrtino premera 7,5 colov do kote 196 m. Obložna cev vrtine je bila spodaj perforirana na dolžini 5 m. Da bi preprečili pretakanje vode iz zgornje, bolj prepustne plasti ob ceveh vodnjaka navzdol v perforirani del vrtine, je bila do kote 201 m zabita še neperforirana cev premera 20 colov. Enako so bile izvedene tudi piezometrske vrtine. P2T, PM in P29 (3. si.). 2e prvi podatki črpanja so pokazali, da je izolacija pliocenskega proda od pleistocenskega popolnoma uspela; že pri Q = 0,2051/sek je znašala depresija v vrtini 3,6 m, v piezometrskih ceveh pa nekoliko manj. Poizkusno črpanje je trajalo 10 dni pri 6 različnih količinah Q od 0,205 do 1,7 1/sek (4. si.). Pri vseh poizkusih smo črpali tako dolgo, da smo dosegli stacionarno stanje, razen pri Q = 1,7 1/sek, ko je gladina vode v vodnjaku padla pod spodnji rob črpalke in je bilo črpanje prekinjeno. Za izračunanje vrednosti k iz črpalnih poizkusov, pri katerih je bilo doseženo stacionarno stanje, smo uporabili Thiemovo enačbo za dotok vode k vodnjaku iz vodnega horizonta pod pritiskom: fc_ 0,366 Q l0g'r2-l0g-ri M(si~si) T2 = razdalja piezometra P28 od središča vrtine r/ = razdalja piezometra P27 od središča vrtine si — znižanje gladine vode v piezometru P27 med črpanjem 5? = znižanje gladine vode v piezometru P.>8 med črpanjem M ~ debelina vodnega horizonta — dolžina perforiranega dela črpalne vrtine. Razmere med črpalnim poizkusom so približno ustrezale pogojem Thiemove enačbe. Pri računanju smo privzeli, da je plast pliocenskega proda in peska nad perforacijo v vrtini do kote 214 m, kjer je meja med pliocenskim in pleistocenskim prodom, nepropustna. Ta predpostavka ni povsem točna, vendar lahko z gotovostjo trdimo, da je prepustnost pliocenskih plasti v navpični smeri neznatna. Med vrtanjem je namreč voda dotekala v vrtine le na odsekih čistega peščenega proda. Na odsekih vrtine v meljastem produ, glini in konsolidiranem pesku ni bilo znatnejšega dotoka vode, kar smo ugotovili po znatnem upadanju vodne gladine v vrtini, potem ko smo izolirali čiste peščene prodne plasti z obložno cevjo. Vrtali smo brez izplake, zato se voda v vrtini ni tako hitro dvignila do prvotne višine, ko smo izvlekli jedrno cev. Enake pliocenske plasti nastopajo tudi pod dnom vrtine, tj. pod koto 196 m. Zato smo privzeli, da so tudi te plasti v navpični smeri neprepustne in da iz njih med poizkusnim črpanjem voda ni dotekala v vodnjak. o 0<-rx«*>»»m>tfrs.®<7>© .-NO -T U"> DEPRESIJA {m) DEPRESSION Q trn/h ) SI. 4. Diagram črpanja iz vrtine v vodnjaku BV2 Fig. 4. Diagram of the pumping test with the drill hole located within the well BVo Q(m/h) 12 3^567 SI. 5. Diagram odvisnosti depresije A od količine črpane vode Q v vrtini in piezometrskih ceveh Fig. 5. Diagram showing the relations between drawdown A and drill hole discharge Q Opazovanja so potrdila našo domnevo, da je depresija v vodnjaku in piezometrskih ceveh sorazmerna količini črpane vode, kar je značilno za vodne horizonte pod pritiskom (5. si.). Vrednost koeficienta prepustnosti k je: za Q = 0,51/sek k = 9,04.10"« m/sek za Q = 0,851/sek k = 9,48.10-* m/sek V obeh primerih smo uporabili podatke iz piezometrskih cevi P27 in P2tJ, ki so najbolj zanesljivi. Med črpanjem so bile v piezometrski cevi Pa9 malenkostne depresije, v vrtini pa je bila depresija večja, kot bi ustrezalo Thiemovi depresijski črti, in sicer zaradi izgub pritiska pri pretakanju vode skozi perforirano cev (6. si.). Kot debelino vodnega horizonta M smo privzeli dolžino perforiranega dela vodnjaka. Vodni horizont M vsebuje več plasti prepustnega peščenega proda, vloženih v zelo malo prepusten pesek in meljast prod. Izračunana vrednost koeficienta k je srednja vrednost prepustnosti močno prepustnih in zelo malo prepustnih pliocenskih plasti. Vrednost koeficienta k smo zaradi kontrole računali tudi po grafični metodi, ki jo je predložil Cast any (1963). Po tej metodi računamo k po enačbi j, __ 0,366 ,Q c T = k.M c =--; vrednost c odčitamo neposredno z grafičnega prikaza S (log x) depresije in logaritma razdalje; na ordinato nanašamo vrednosti depresije v navadnem merilu, vrednosti razdalj piezometrov od središča vrtine pa v logaritmičnem merilu. Pri dveh različnih vrednostih Q smo dobili naslednji vrednosti za k: Pri Q = 1,8 ms/h m 0,366.0,0005 J irt , , T = ----= 4,47.10"5m2/sek 4,1 T 4 47 10"5 fc = . _ = ——'-= 8,93 .10"6m/sek M 5 Pri Q = 3,06m3/h „ 0,366.0,00085 9, . T = -!-= 478.10"5m2/sek 6,5 k = 9,57.10*6m/sek log razdalje x(m) log of distance SI. 6. Depresija v vrtini in piezometrih pri črpanju 1,8 m3/h in 3,06 m", h Fig. 6. Depression of the water table in the drill hole located within the well EVo and piezometers at discharges l,8nr7h and 3,06 m9/h Rezultati, ki smo jih dobili z računanjem na oba načina, so skoraj enaki. Izračunana vrednost koeficienta k je srednja vrednost prepustnosti 5 m debele plasti pliocenskega proda, iz katere je med črpanjem dotekala voda v vrtino. Pliocenski prod sestoji iz plasti manj prepustnega melja-stega proda in iz plasti bolj prepustnega čistega peščenega proda. To velja za celotno območje, zato lahko privzamemo izračunano vrednost koeficienta k za ves pliocenski prod. Kemična analiza vode, ki je tekla med črpanjem iz vrtine, je pokazala, da se njena sestava močno razlikuje od sestave vode iz zgornjega vodnega horizonta. Trdota vode v spodnjem horizontu je le 11,55° dH, v zgornjem pa 14,6® dH. Po podatkih poizkusnega črpanja iz vrtine v vodnjaku BV2 je bil izdelan glavni projekt. Projektant je predvidel kopanje gradbene jame brez zagatnih sten s črpanjem vode, ki bo dotekala iz pleistocenskega proda. Dotoka vode iz pliocenskega proda ni upošteval, ker vrednost koeficienta k kaže, da bo zelo majhen. Prav tako je bilo mogoče po podatkih vrtanja sklepati, da v pliocenskem produ ne bo pojavov tekočega peska. Po končanem izkopu gradbene jame so opazovanja potrdila pričakovanje, da bo dotok vode iz pliocenskih plasti le neznaten. Točnih podatkov o količini vode ni bilo mogoče zbrati, ker zid, temeljen v pliocenskih plasteh, ki brani prelivanje vode, dotekajoče iz pleistocenskega proda v gradbeno jamo, ni popolnoma vodotesen. Po približni oceni dotok iz pliocenskega proda ni presegal 10 1/sek. GEOLOGIC AND HYDROGEOLOGIC CONDITIONS IN THE POWERHOUSE SITE OF THE SREDNJA DRAVA I POWER PLANT Abstract The powerhouse of the Srednja Drava I power plant is projected on the Pleistocene terrace of Drava river near the main road Maribor— Ptuj at the village Zlatoličje. The foundations of the powerhouse are proposed on the plus 201 m level in the depth of 37,5 meters and 29 meters below the ground water table. In the powerhouse area extensive geologic and hydrogeologic researches have been carried out (Fig. 1). According to data obtained by bore holes, the terrace is composed to the depth of approximately 25 meters by loosely packed Pleistocene gravel; below it is a layer of densely packed Pliocene gravel with intercalations of sand, conglomerate and indurated clay. These intercalations horizontally thin out at a short distance. From the grading analysis of the Pleistocene and Pliocene gravels emerged that the Pleistocene gravel contains only an inisignificant admixture of silt and from 35 °/o to 57 °/o sand. The particle seize of Pliocene gravel is mostly very thin, containing from 11 °/o to 35 °/o silt and 20ft/o to 62 °/» sand. Standard penetration tests carried out in the Pliocene gravel showed that it is much consolidated. On account of coarse particles the results of the same tests in the Pleistocene gravel are not reliable. The Pleistocene and the Pliocene gravel differ from one another very much as to the value of volume weight. This comes up at the former at most to 2,04 t/cu. m and at the latter from 2,06 to 2,3 t/cu. m. From drilling examinations emerged that Pleistocene gravel at corresponding conditions turns into running sand, whereas this is not the case with Pliocene gravel. All these investigations show that the Pliocene gravel under the foundations of the powerhouse can be loaded with more than 5 kp/sq. cm. The 'additional intensity of loading soil will not be significant because unloading due to excavations will reach the value of 52,5 t/sq. m. The conditions of the powerhouse foundations are therefore favourable. Excavations will mostly take place under the ground water table. The Pleistocene gravel could be partly excavated by means of power equipment. Before the excavation of dense packed Pliocene gravel, however, water will have to be removed from the building ground by pumping. For the excavation project the quantity of Svater inflow from Pleistocene and Pliocene gravels had to be evaluated. For this purpose permeability tests of Pleistocene and Pliocene gravels were carried out and that in laboratory and under field conditions with bore holes and pumping tests. At the village Zlatoličje two wells were dug out, BV-1 and BV-2. The screen of the shallow well BV-2 was sunk and perforated only within the section of Pleistocene gravel. The same operation was performed at the deeper well BV-1 only in the lower part of the Pliocene gravel. Pumping test showed the value of permeability coefficient k of the Pleistocene gravel from 4,1 to 4.63.10-1 cm/sec and of the Pliocene gravel 3.10~2 cm/sec (Fig. 2). Laboratory investigations of Pliocene gravel, pumping tests and permeability measurements at drilling gave much lower values of the permeability coefficient k and that from 5,05.10"2 to 5,3.10~5 cm/sec. A particular attention raised the chemical analyses of water from both wells because they showed nearly the same quality of water. Owing to a different gravel composition a corresponding difference in the chemical composition of water should be expected. The suspicion gained ground that during the pumping test water penetrated in the perforated portion of the well BV-1 not only from the Pliocene gravel, but also along the casing exterior from the overlaying, very permeable Pleistocene gravel. In any case in the Pliocene gravel on account of the different lithologic composition a somewhat different quality of water could be expected. By ordre of the Dravske Elektrarne another pumping test had to be carried out. Consequently the Geological Survey of Ljubljana made a drilling hole in the Pliocene gravel within the shallow well BV-2 (Fig. 3) The pumping test proved to be successful. Measurements of the water table in the test hole as well as in the piezometers showed a great depression and that already at Q = 0,205 litre/sec (Fig. 4). Chemical analyses of water, flowing from the well during the pumping test, showed that its composition greatly differs from the one of the upper water horizon. Whereas the water hardness from the Pleistocene gravel reaches 14,6° dll, the one from the Pliocene gravel comes up only to 11,5° dH. At the stabilized water level the value of k was evaluated from pumping test data- applying the same equation as for the flow to a well, penetrating a confined aquifer (Fig. 5). Observations during the pumping test showed that the drawdown in the testhole and in the piezometers was proportionate to the discharge rate. This is a characteristic for the confined aquifers. The calculated value of k oscillates between 9,06 to 9,48.10~4 cm/sec. On the basis of these data the main project provided an excavation without sheet pile courtains and without grouting but pumping of water flowing from the Pleistocene gravel. The discharge from the Pliocene gravel has not been taken into account owing to the very low value of k. According to drilling data no running sand could be expected in the Pliocene gravel. For this reason the foundations of the powerhouse have been projected directly on the Pliocene gravel without any consolidation works. Later observations during the excavation entirely confirmed all the foreseeings regarding the discharge of water from the Pleistocene and Pliocene gravels and the possibility of foundations on the Pliocene gravel (Figs. 7 A and 7 B). LITERATURA Bogomolov, G. V., in Silin-Bekčurin, A. I., 1959, Specijalna hidrogeologija. »Gradjevinska knjiga«, Beograd. Castany, G., 1963, Traite pratique des eaux souterraanes. Dunod, Paris. K e r i n, A., 1965, Diplomska naloga št. 453/65. Arhiv Fakultete za arhitekturo. gradbeništvo in geodezijo v Ljubljani. T odd, D. K., 1964, Ground water hydrology. John Wiley & Sons, Inc., Publishers. Zlebnik, L., 1963, Pregledno geološko poročilo k projektu elektrarne prve stopnje Srednje Drave. Poročilo v arhivu Geološkega zavoda v Ljubljani. z B SI. 7. — Fig. 7 A. Pogled na zahodni del gradbene jame A. View of the western part of excavation B. Pogled na severni in vzhodni del gradbene jame B. View of the northern and eastern part of excavation p = pleistocenski prcd — Pleistocene gravel pi = pliocenski prod - Pliocene gravel i = izvir v pleisfcocenskem produ — Flow of water from Plelistocene gravel v - vod.a, ki teče proti črpališču — Water flowing to pumping station č = črpališče — Pumping station z - Betonski zid, ki preprečuje prelivanje vode v gradbeno jamo — Concrete wall protecting the excavation from water O BARITU NA SLOVENSKEM Milan Fabjančič Uporaba barita Uporabnost barita je zelo mnogostranska. Največ ga porabijo za težke izplake pri globinskem vrtanju, za proizvodnjo litopona in barv, v kemični industriji in za proizvodnjo baritnega cementa. V ZDA je leta 1959 od celotne potrošnje barita odpadlo 95 °/o na globinsko vrtanje, na industrijo gumija 2 %, na industrijo stekla 1 °/o, na industrijo barv 1 °/o in na druge potrošnike 1 °/o. Struktura potrošnje barita se v tej državi zelo počasi spreminja in ostaja po več let skoraj enaka. Isto velja tudi za druge industrijske države. Za posamezne namene postavljajo za kvaliteto barita različne zahteve, ki jih je možno izpolniti z manj ali bolj zapletenimi proizvodnimi operacijami. Zahteve se nanašajo na kemično čistost (maksimum škodljivih primesi, minimum koristnih snovi), specifično težo, beloto, konsistenco, vsebino vlage in na druge lastnosti surovine. Za vsako vrsto uporabe barita postavljajo posebno strukturo pogojev, z drugimi besedami,.. pri določeni uporabi barita so važne samo določene lastnosti. Seveda pa se tudi pri enaki uporabi često razlikujejo pogoji različnih potrošnikov, zlasti če so iz različnih držav. Zato se mora proizvajalec tehnično prilagoditi vsaj glavnim zahtevam tržišča, oziroma tistemu krogu kupcev, kjer doseže najugodnejše poslovne rezultate. Barit je potrebno prebirati, prati, drobiti, mleti, flotirati, žariti, beliti, elektromagnetno čistiti od železa, kemično predelovati in pakirati. Tako imenovani petrolej ski barit primešajo izplakam za vrtanje globinskih vrtin. S težkimi izplakami obvladujejo ogromne pritiske v globinah, pa tudi pritiske plinov v ležiščih nafte in tako preprečujejo erupcije. Pri petrolejskem baritu je važna specifična teža 4,2 do 4,3, takšna granulacija, da gre 95 %> barita skozi sito z luknjicami premera 42 mikronov (325 mesh) in vsebina BaS04 do 94 «/o. Poleg tega ne sme vsebovati v vodi topnih soli. Za izdelavo litopona zahtevajo običajno kosovni barit s 93 °/o do 96 °/o BaS04, ki lahko vsebuje največ 1 °/o FeaO, in 1,5 SiO,; Ala03, CaO in MgO pa največ 0.5 °/o. Ne sme vsebovati F, Zn in Pb. Litopon je pigment, ki vsebuje 70 °/o BaS04 in 30 °/o ZnS; uporabljajo ga za proizvodnjo oljnih in slikarskih barv ter emajlnih premazov. Podobni so pogoji za barite, ki jih uporablja kemična industrija za proizvodnjo barijevega sulfata, karbonata, klorida, oksida, hidroksida, nitrata in še mnogih drugih spojin. Kot polnilo uporabljajo bel prirodni barit, kemično zelo čist, ter drobno in precizno mlet, tako da imajo zrnca premer pod 42 mikronov. Dodajajo ga barvam, lakom in finejšim vrstam papirja. Kot polnilo uporabljajo barit tudi pri proizvodnji gumija, impregniranju tkanin, linoleja in insekticidov. V ta namen mora barit vsebovati vsaj 96 °/o barijevega sulfata in manj kot 0,2 do 1 °/o FegOu. Steklu dodajajo barit kot talilo in bistrilo. Potrebne učinke dosežejo z njegovim oksidacijskim delovanjem. Steklarski barit ne sme vsebovati težkih kovin, kot npr. Fe, Cu, Co, Cr, Ni, ker njihovi oksidi barvajo steklo. Zn in Pb ne motita, FegOs pa sme vsebovati le 0.1 %>. Zrnca morajo imeti premer 0,08 mm ali manj. Za cementni barit je dovolj, če vsebuje 80 Vo do 92 °/o BaSOj, mora pa imeti specifično težo 4,15 in ne sme vsebovati snovi, ki škodljivo vplivajo na cement ali armaturo. Pb je škodljiva komponenta, koristna pa je, če barit vsebuje do 8 ali največ do 10 °/o SiOž, 2,5 do 3 °/o AlgOs in toliko železa, da je utežno razmerje FeOa: Al^O;} — 1:2. Če vsebuje barit malo železa in aluminija, mu dodajajo boksit, če pa vsebuje mnogo železa, mu je treba dodajati glinico, ki pa je precej draga. Barit naj bo mlet do takšne granulacije, da ima 90 % zrnc premer manjši od 90 mikronov. Uporabljajo ga za izdelovanje cementa za zaščitne zidove proti radioaktivnemu sevanju, pa tudi kot dodatek k hladno mešanim asfaltom pri gradnji kvalitetnih cest in pist, za obloge cevovodov, položenih prek rek in močvirij in za podobne namene. Problem proizvodnje barijevih cementov je bil že tudi pri nas postavljen zaradi izrednih lastnosti teh veziv, ki se kažejo: 1. v obstojnosti pri visokih temperaturah do 1730° C in z dodatki še pri višjih, 2. v izredni odpornosti proti delovanju morskih in drugih sulfat-nih vod, 3. v visoki stopnji nepropustnosti za rentgenske in gama žarke. Z lastnostmi baritnih cementov se je ukvarjal B r o n i s k i ; 15 let je izpostavljal prizme iz različnih cementov morski vodi v Črnem morju in je ugotovil, da so baritni cementi proti njej mnogo odpornejši kot drugi, klasični cementi. Zanimiv je Sanielevicijev poskus; z emitiranjem mehkih žarkov gama skozi ovire različnih debelin in materialov je z Geiger-Mullerjevim števcem ugotovil njihovo varovalno debelino pri določenih napetostih rentgenskega sevanja. Rezultate kaže 1. tabela. DEBELINA VAROVALNIH OBLOG PRED RENTGENSKIMI 2ARKI 1. tabela Snov Najmanjša varovalna debelina pred rentgenskimi žarki v mm pri napetosti 60 kV 200 kV Valjana svinčeva pločevina Barijev zaščitni beton Svinčevo steklo Kalcijev zaščitni beton z dodatki Ba Zaščitni betoni z običajnim cementom 0,9 7 8 14 65 4 29 34 60 270 Iz tabele vidimo, da je zaščitni učinek barijevega betona pred rentgenskimi žarki pri napetosti 60 kV in 200 k V blizu zaščitnemu učinku svinčevega stekla. Pri navedenih napetostih rentgenskih žarkov je potrebna dvojna debelina kalcijevega zaščitnega betona, da dosežemo učinek, ki ga ima barijev beton. Zaščitni učinek enako debele valjane svinčeve pločevine je osemkrat večji kot pri barijevem betonu, material za postavitev svinčeve zaščitne membrane pa je približno trikrat dražji kot material za postavitev enakovrednega zidu iz barijevega betona. Že uporabnost barita kaže, da so njegovi veliki potrošniki države z visoko razvito proizvodnjo nafte in sploh dežele z razvito industrijo. Potrošnja barita se namreč razvija vzporedno z razširjanjem njegove uporabe v novih industrijskih panogah in sorazmerno z razvojem industrije, v kateri ga že uporabljajo. Potrošnja barita v industrijsko razvitih državah je skoraj povsod precej večja od njihove lastne proizvodnje. Zato so te države veliki uvozniki barita. To pospešuje proizvodnjo v drugih državah, ki imajo možnosti za proizvodnjo te surovine in je same ne uporabljajo v tolikšni meri, kot jo proizvajajo. Med izvozniki barita so zato povečini industrijsko manj razvite države. Proizvajalci barita pa so razvite in manj razvite države, kar kaže 2. tabela. 2. tabela PROIZVODNJA BARITA V LETU 1962* Dežela V tonah Dežela V tonah Alžirija 19 958 Kanada 207 991 Argentina 18 144 Kitajska 81 647 Avstralija 9 979 Kolumbija 9 979 Avstrija 1 081 Koreja, južna 920 Brazilija 51 002 Maroko 89 793 Burma 4 048 Mehika 318 135 Cile 1 397 Nemčija — zahodna 426 377 Egipt 2 722 Pakistan 2 870 Filipini 416 Peru 95 000 Francija 70 035 Poljska 45 215 Grčija 79 832 Portugalska 2 087 Indija 24 476 Španija 34 019 Iran 15 000 Švica 62 Irska 343 Turčija 1 900 Italija 121 915 ZDA 804 640 Japonska 35 048 Združeno kraljestvo 76 896 Jugoslavija 130 000 ZSSR 181 437 Južnoafriška unija 1699 Iz Bolgarije, Češkoslovaške, Vzhodne Nemčije in Severne Koreje, kjer tudi pridobivajo barit, nimamo podatkov. Iz tabele vidimo, da so bili v letu 1962 največji proizvajalci barita ZDA. Zahodna Nemčija, Mehika, Kanada, ZSSR, Jugoslavija, Italija, Peru. Maroko in Kitajska. Svetovno proizvodnjo barita v letih 1950 do 1962 kaže 3. tabela. * Preračunani podatki iz Minerals Yearbook 1962; US Department of the Interior, Bureau of Mines. 3. tabela SVETOVNA PROIZVODNJA BARITA V LETIH 1950 DO 1962* Leto V tonah Leto 1950 do 1954 povprečno 1823 000 1955 2 450 000 1956 2 812 000 1957 3 175 000 1958 2 359 000 1959 1960 1961 1962 V tonah 2 722 000 2 767 000 2 685 000 3 003 000 Jugoslavija proizvaja kosovni in mleti barit. Proizvodnja se je začela razvijati že med obema svetovnima vojnama, vendar v majhnih količinah. V svetovnega proizvajalca barita se je naša država razvila po drugi svetovni vojni. Po približnih podatkih je v Jugoslaviji naraščala proizvodnja barita kot kaže 4. tabela. 4. tabela PROIZVODNJA BARITA V JUGOSLAVIJI Leto V tonah Leto V toinah 1939 5 000 1955 88 123 1951 24 447 1956 93 918 1952 34 819 1957 120 780 1953 81 114 1962 130 000 1954 95 046 V ZDA krijejo z lastno proizvodnjo le približno polovico barita za domačo potrošnjo in so zato največji uvoznik kosovnega barita na svetu. Ameriški rudniki v notranjosti kontinenta so precej oddaljeni od velikega dela predelovalne industrije, ki je koncentrirana v bližini atlantskih pristanišč. Zato sorazmerno majhni stroški ladijskega transporta omogočajo sosednjim državam (Kanada, Mehika), pa tudi bolj oddaljenim, izvoz barita v ZDA. Mehika in Kanada sta glavna dobavitelja barita ZDA, v zadnjih letih pa se jima je pridružil še Peru. Poleg teh držav se na tem tržišču pojavljajo še Grčija, Španija in Maroko. Ker so jugoslovanski bariti kvalitetnejši od mnogih drugih, so ZDA za nas pomembno tržišče. Povpraševanje po naših baritih je tu vedno večje od možnosti naših dobav. Zahteve glede kvalitete niso stroge, vendar so cene v tem času nizke in se gibljejo okoli 10 $ za tono kosovnega barita. Avstrija je naše baritno tržišče zaradi ugodnega transporta. Uvaža 3500 do 5000 ton barita letno. Zahodna Nemčija je drugi največji proizvajalec barita na svetu. Kljub temu uvaža okoli 20 000 ton barita letno. Postavlja pa zelo stroge pogoje glede kvalitete. Sedaj v to državo ne izvažamo, ker močno konkurirata Španija in Maroko, ki imata ugodnejše transportne možnosti. Velika Britanija postavlja ugodnejše cene za barit kot nemško tržišče. * Preračunani in zaokroženi podatki iz Minerals Yearbook 1959, 1962: US Department of the Interior, Bureau of Mines. Francosko tržišče ima za naš barit podobne pogoje kot angleško. ZSSR uvaža predvsem kosovni barit in postavlja sorazmerno stroge zahteve glede hvalitete. Vendar izvažamo na to tržišče tudi precejšnje količine mletega barita. Madžarska uvaža predvsem kosovni beli barit, z njim pa še nekaj sivega kosovnega in mletega. Kupca našega barita sta lahko tudi češkoslovaška in Poljska. Kot konkurent se na vzhodnem tržišču pojavlja Bolgarija, vendar ima majhno proizvodnjo in slabo kvaliteto. Za jugoslovanske barite pridejo v poštev tudi tržišča bližnjega in srednjega vzhoda, kamor do sedaj še nismo izvažali večjih količin. Tako v zahodnih kot v vzhodnih deželah je povpraševanje po naših baritih večje kot naša ponudba. Iz zgodovine proizvodnje barita v Sloveniji V Sloveniji sta doslej obratovala dva baritna rudnika Pleše pri Škofljici in Litija. V obeh so prvotno pridobivali druge mineralne surovine; pred prvo svetovno vojno so v Plešah odkopavali le svinčevo rudo, v Litiji pa poleg svinčeve še živosrebrno, cinkovo, železovo in tudi sre-brovo. Barit so začeli pridobivati šele po prvi svetovni vojni. Kvaliteto barita iz Pleš in Litije kaže 5. tabela. 5. tabela KEMIČNA SESTAVA BARITA IZ PLES IN LITIJE Sestavina Pleše Litija % % BaSC>4 93 do 99 88 do 95 Si02 0,1 do 4,8 3 do 6 Fe 0,07 do 0,12 0 do 2,93 A12Os 0,11 do 0,95 1,05 do 1.26 CaCOg 0,07 do 1,05 MgCOs 0,0 do 0,90 do 0,35 Vidimo, da je barit iz Pleš precej boljši, ker vsebuje skoraj 5°/o več BaSOj ter manj SiOž in Fe. Zanimivo je, da je v litijskem baritu tudi več kalcita kot v baritu iz Pleš. Takšne prednosti surovine so vplivale, da so v Plešah začeli pridobivati barit prej in v večjem obsegu kot v Litiji. Leta 1919 je prvič financirala organizacijo proizvodnje barita Jadranska banka s sedežem v Ljubljani. Z delom so začeli na zahodni strani hriba Celo, nad vasjo Dule. Na vzhodni strani istega hriba pa je začela v obdobju med prvo in drugo svetovno vojno z eksploatacijo barita Tehniška komercialna družba, ki je tudi imela svoj sedež v Ljubljani. Proizvodnja je bila majhna, v letih 1934 do 1945 je znašala približno 6000 ton barita. Tudi iz litijske jame, kjer je po prvi svetovni vojni odkopavala svinčevo rudo rudarska družba Litija, so že od časa do časa prebrali kakšno tono barita. Belega so prodajali po 4000 din za 10 ton, rjavega pa po 1500 din za enako količino. Med okupacijo so Nemci poskusili organizirati pridobivanje barita v Litiji, čeprav zaradi velikega odstotka SiOj>, ki je znašal 8 %> do 10 °/o, z litijsko surovino niso bili zadovoljni. Zaradi primesi železa so jo ocenili kot neprimerno za industrijo barv. Kljub tem neugodnim lastnostim so v Litiji leta 1943 nakopali 2056 ton barita, leta 1944 pa še 243 ton. Vseboval je 88.1 °/o BaSOj in 9,2 °/o SiC>2. Obogatili so ga na kraju samem in pošiljali v Celje, kjer so ga uporabljali za izdelavo litopona. Po vojni so v Plešah takoj obnovili proizvodnjo barita na hribu Čelo. Temu revirju se je leta 1954 pridružil še revir Vrhovka. V Litiji se je začela proizvodnja barita šele leta 1952, ko sta se rudnika Pleše in Litija združila pod imenom Posavski rudniki. V letu 1956 so na obeh rudnikih zgradili mokromehanični separaciji. Zato se je v letih 1956 in 1957 proizvodnja barita močno povečala. Istočasno pa so začeli v Litiji, prvič po drugi svetovni vojni, ponovno pridobivati svinčev koncentrat. Po letu 1957 se je proizvodnja barita v Litiji zaradi poslabšanja konjunkture zopet zmanjšala, konec leta 1959 pa je bila ustavljena. Med tem časom je naraščala proizvodnja svinčevega koncentrata. V rudniku Pleše pa so kontinuirano odkopavali barit do leta 1963, ko so morali prenehati, ker so zaradi mnogo preskromnih raziskovalnih del izčrpali zaloge. Proizvodnjo v rudnikih Pleše in Litija nam kaže 6. tabela. 6. tabela PROIZVODNJA RUDNIH KONCENTRATOV V LITIJI IN PLEŠAH Proizvodnja v tonah Litija Pleše Skupaj PbS BaS04 ZnS BaS04 PbS BaS04 ZnS 1946 _ _ _ 591 __ 591 1947 — — — 6005 — 6005 _ 1948 — — — 7543 — 7543 _ 1949 — — — 5368 — 5368 — 1950 — — — 2647 — 2647 _ 1951 — — — 1870 — 1870 _ 1952 — 473 — 4070 — 4543 _ 1953 — 5933 — 5100 — 11033 — 1954 — 3548 — 4523 — 8071 _ 1955 — 2887 — 5575 — 8462 _ 1956 118 4200 — 6415 118 10615 _ 1957 50 6600 — 6635 50 13235 _ 1958 650 1243 — 5775 650 7018 _ 1959 620 910 — 5260 620 6170 _ 1960 724 247 — 5290 724 5537 _ 1961 735 — — 6425 735 6425 _ 1962 939 — — 6000 939 6000 _ 1963 952 155 — 5079 952 5234 _ 1964 512 1782 259 — 512 1782 259 1965 388 1729 — — — — — Z novim letom 1961 je bil litijski rudnik priključen k rudniku Mežici kot poslovna enota. Novo matično podjetje je zgradilo flotacijo s kapaciteto 100 t rude/24h, ki je začela obratovati poleti istega leta. S tem je bila povečana proizvodnja galenitnega koncentrata. Nekaj let pozneje so uredili tudi pridobivanje baritnega in sfaleritnega koncentrata. Izkoristki so znašali okoli 90 °/o Pb za svinčevo rudo, 92 °/o do 93 ft/o Zn za cinkovo rudo in 60 ®/o do 70 °/o za baritno rudo. Z izboljšanim tehnološkim postopkom bi mogli predelati stare odvale, ki vsebujejo l,83°/»Pbf 0,47 %>Zn in 30%BaS04. Z rekonstrukcijo izbiralnice bi povečali njeno predelovalno zmogljivost za 50°/o, obenem pa bi jo usposobili za pridobivanje barita iz starega flotacijskega odvala z zadovoljivim izkoristkom. Redna proizvodnja baritnega in cinkovega koncentrata se je začela šele v letu 1964. Rekonstrukcija izbiralnice pa v tem času še ni bilo opravljena. Nahajališča barita v Sloveniji Proizvodnja barita v Sloveniji se je razmahnila do pomembnejšega obsega šele po drugi svetovni vojni. Ta mineral so imeli prej za spremljajočo jalovino svinčeve in tudi cinkove rude. Zato ga stara poročila poredko omenjajo in še to le mimogrede. Ves barit, ki so ga odkopali obenem s svinčevo rudo pred prvo svetovno vojno, in večji del barita, odkopanega med obema vojnama, leži na odvalih. Tudi po drugi svetovni vojni je zanimanje za svinčevo in cinkovo rudo često puščalo barit v senci. Zato so doslej zbrani podatki nepopolni. Študij nahajališč, kjer so bili registrirani pojavi barita ter svinčeve in cinkove rude, bi nam dal nove podatke o njihovem gospodarskem pomenu. Vendar nam rudišča, kjer so doslej že odkopavali galenit, sfalerit ali celo barit, kažejo, s kakšnimi baritnimi pojavi lahko računamo v Sloveniji. Doslej smo po literaturi in lastnih zapiskih ugotovili naslednja nahajališča s podatki o baritnih pojavih: Arhov graben nad Zavrstnikom pri Litiji Belščica v Karavankah na območju Jesenic Brezno pri Laškem Budna vas pri Radečah Dobrava pri Litiji Dule pri Škofljici Hrastarija vzhodno od Litije Lokavec pri Rimskih Toplicah Maljek vzhodno od Litije Mamolj vzhodno od Litije Marija Reka pod Mrzlico Na Jezeh vzhodno od Litije Odanče južno od Golice nad Jesenicami Pasjek pod Polšnikom Ples pri Kozjem Pleše vzhodno od Škofljice Počivalnik severozahodno od Tržiča Podčešje vzhodno od Litije Podkraj pri Hrastniku Probsov kamnolom zahodno od Zavrstnika Sitarjevec pri Litiji Sancetova ruda blizu Loga pod Mangartom Šmarje pri Grosupljem Striglavi jarek pod Mamoljem Volčja jama pri Zavrstniku Vrbetov jarek vzhodno od Litije Vrhovka pri Škofljici Zagorica pri Litiji Zavrstnik pri Litiji Posamezna od teh nahajališč so v severozahodni Sloveniji, v Karavankah in pod Mangartom, vsa druga pa v trikotniku Škofljica—Celje— St. Janž v osrednji Sloveniji na območju Posavskih gub. A. Barit v Karavankah in pod Mangartom Na tem območju so doslej znani le štirje pojavi barita, in sicer: Šancetova ruda v bližini Loga pod Mangartom. Barit se tu pojavlja kot spremljevalec galenitne rude v plasteh srednje triade. Poleg barita in galenita najdemo še pirit, limonit in sadro. Vsi ti minerali zapolnjujejo prelome s smerjo SSW—NNE ali pa jih spremljajo. Na tem območju je obratoval rudnik svinca. Belščica v Karavankah na območju Jesenic. Tudi tu se barit pojavlja v kompleksni mineralizaciji s sideritom, piritom, galenitom in sfaleritom v bližini rova Urbas. Odanče nad Jesenicami južno od Golice. Barit spremlja galenitno-sfaleritno rudo. Počivalnik severozahodno od Tržiča. Tu so našli barit z malahitom, azuritom in tenantitom. O ekonomski vrednosti teh pojavov ni podatkov. B. Barit v Posavskih gubah Večina nahajališč barita v Posavskih gubah je v ožjem območju litijske antiklinale, kjer so najzahodnejši izdanki okoli Pleš, najvzhodnejši pa, z izjemo Plesa, pri Budni vasi, na poti od Radeč pri Zidanem mostu proti Št. Janžu. Tudi v teh mejah izdanki ne kažejo kontinuitete, ampak so razbiti na posamezna območja, kjer so bolj strnjeni. Največje je centralno območje širše okolice Litije. Tu so baritni pojavi razvrščeni južno od Save, od Volčje jame na zahodu, do Pasjeka in Štriglavega jarka na vzhodu; razdalja med krajnimi pojavi znaša okoli 12 km. Izdanki svinčeve rude pa to območje še nekoliko razširjajo. Tu so znana od zahoda proti vzhodu naslednja nahajališča barita: Volčja jama, Probsov kamnolom, Arhov graben, Zavrstnik, Sitarjevec, Dobrava, Zagorica, Na jezeh, Maljek, Podčešje, Vrbetov jarek, Hrastarija, Mamolj, Štriglavec. Jugovzhodno od Ljubljane so znani pojavi barita v okolici Škofljice: Pleše, Dule, Vrhovka, Šmarje. Redko razporejena so nahajališča barita na območju Št. Janž—Laško—Trbovlje: Budna vas, Podkraj, Lokavec, Brezno in Marija Reka. Od vseh teh nahajališč sta zunaj litijske antiklinale le Brezno in Marija Reka, ki je hkrati najsevernejši znani pojav barita na območju Posavskih gub. Osnovni podatki o najdiščih so naslednji: a) Območje Št. Janž — Laško — Trbovlje Budna vas. Tu prevladujejo paleozojske plasti s kremenovim peščenjakom in konglomeratom ter glinastim skrilavcem. Pojavljajo se tudi werfenski skrilavec in peščenjak ter triadni apnenec. Baritno-galenitno-cinabaritna ruda zapolnjuje prelome. Takšne pojave moremo opazovati v več krajih. Tu je obratoval do začetka našega stoletja rudnik svinca v dolini potoka Knapovka. Podkraj. Na desnem bregu Save med Hrastnikom in Zidanim mostom je bil v prejšnjem stoletju rudnik svinca. Poleg PbS se tod pojavljata še barit in cinabarit. Lokavec. Osnovo terena sestavljajo plasti paleozojskega kremenovega peščenjaka in konglomerata, ki jih delno pokrivajo werfenski skladi in ponekod školjko viti apnenec. Rudni minerali, med njimi prevladuje ga-lenit, zapolnjujejo prelome in razpoke v peščenjaku in konglomeratu. Barit nahajamo tu le v redkih kristalih. Lokavec je bil rudnik svinca, kjer so zadnjikrat rudarili med prvo svetovno vojno. Brezno pri Laškem. Barit v tej lokalnosti omenja Jelene (1953). Marija Reka. Star rudnik svinca in živega srebra. Zadnja poskusna proizvodnja živega srebra je bila leta 1958. Na mladopaleozojskem temnem glinastem sljudnatem skrilavcu leži werfenski bel in rdeč sljudnat peščenjak,. ki vsebuje manjše leče apnenca in dolomita. Plasti vpadajo proti jugu pod koti 30° do 60°. Samorodno živo srebro in cinabarit se pojavljata v nepravilnih majhnih lečah. Razpoke z vpadom 150/50° so zapolnjene s kremenom, baritoni in cinabaritom. Sedlar (1950) navaja, da so baritne žile debele do 40 cm. Tudi M a k u c omenja barit in kremen kot spremljevalca cina-barita. Po njegovih poročilih so posebno bogate s cinabaritom prav baritne žile. Ples pri Kozjem. Iz te lokalnosti omenja baritni pojav Jelene (1953). V opisanih nahajališčih barita so v kompleksnih rudah tudi pojavi sorodnih rud, in sicer: 1. V širši okolici Budne vasi so znana nahajališča svinčevo-živo-srebrovih rud v krajih Trebeljno-Srednik (Pb, Zn), Log (Pb), Kompolje (Pb, Zn), Brunska gora (Pb). To območje prehaja v okolici Radeč v območje bakrovih rud z najdišči Močilno (Cu), Sv. Križ (Cu) in Laški potok (Pb). Zahodneje najdemo svinčevo rudo v Padežu in St. Jurju pod Kumom. V okolici Radeč je še več izdankov bakrove rude. 2. Na območju Podkraja in Lokavca se pojavlja mineralizacija s svincem v Velikih Širjah pri Zidanem mostu, Loki in Rudi, medtem ko tvorijo pojavi v Dobravi (Pb), Stranju (Pb, Zn), Zabukovju (Pb), Ledini (Pb, Zn), Tržišču (Pb, Zn) in Mokronogu (Pb, Zn) zunanjo cono rudnih pojavov baritnega območja. 3. V okolici Brezna pri Laškem in Marije Reke ni drugih znanih baritnih pojavov, pač pa so vzhodno od tod še nahajališča sorodnih rud: Zikovica pri Laškem (Pb), Padež (Pb), Svetina (Pb), Celje-Stari grad (Hg). 33 — Geologija št. 9 513 b) Okolica Škofljice Pleše. Jedro doslej znanih pojavov barita na tem območju je v hribu Čelo (421 m) nad vasjo Dule. Osnovo rudišča sestavlja karbonski kremenov peščenjak, ki tu in tam prehaja v kremenov konglomerat. Ti kamenini često prekriva temen glinasti skrilavec, ki delno tvori talnino triadnega dolomita. Ekonomsko najpomembnejša orudenenja so na kontaktu glinastoskrilave krovnine mladopaleozojskega peščenjaka s triadnim dolomitom v obliki leč, ki dosegajo debelino 0,3 do 4 m, horizontalno dolžino 50 do 100 m in širino 50 m. Leče so s kontaktom paleozoik-triada vred nagnjene pod približno 40° proti severovzhodu. Manjše leče barita imajo smer tudi pravokotno na smer večjih. Barit se, razen v kompaktnih telesih, više pojavlja tudi v samem dolomitu, in sicer kot vezivo v ožjih razpokanih in zdrobljenih dolomitnih conah, redko debelejših od 1 m. Prav tako sega barit v tanjših žilicah v globino, kjer često spremlja galenit v poroznem peščenjaku. Globlje se pojavlja tudi sfalcrit. Mejni nivo med zgornjim, baritnim delom rudišča in spodnjim, baritno-galenitno-sfaleritnim delom je približno na višini izvoznega rova Celo ( + 320 m). Kaže, da so rudonosne raztopine prihajale v to območje po prelomih smeri NW—SE. Posebno ugodni pogoji za koncentracijo orudenenj so obstajali na krajih, kjer so raztopine po razpokah naletele na karbonatne kamenine, to je na kontaktu triadnega dolomita in plasti mlajšega pa-leozoika. V prejšnjem stoletju so v tem rudišču odkopavali svinčevo rudo. Barit so začeli izkoriščati po prvi svetovni vojni. Vrhovka. Tu so nekoč izkoriščali svinčevo rudo, ki je poleg barita v podobnem geološkem položaju kot v drugih delih rudišča Pleše. Dule. Tudi tu so v preteklem stoletju odkopavali svinčevo rudo. Šmarje pri Grosupljem. Izdanek barita z galenitom po Jelencu (1953). V širši okolici so znani še naslednji sorodni rudni pojavi: Molnik (Pb, Zn), Podlipoglav (Pb) in Sostro (Pb). c) Širša okolica Litije Volčja jama. Stara dela pod Ščitom in Jastrebnikom. Tu je bil rudnik s topilnico. Pri Andrejčku pri mlinu so sledovi starih rovov in žlindre. Omenjajo izdanke svinčeve rude in izdanke barita. Probsov kamnolom zahodno od Zavrstnika. Ob cesti Zavrstnik—Ljubljana, med Olbanom in Mlavčarjem, so v Probsovem kamnolomu sledovi galenita in barita. Arhov graben. Ob poti od Potočnika proti Zavrstniku je žila barita z limonitom in goethitom, debela 50 cm. Ob isti poti je izdanek barita ob vznožju pobočja nad kmetijo Arh. 2ila je debela 60 cm. Zavrstnik. To rudišče je pod južnimi obronki hriba Sitarjevec na območju naselja Zavrstnik. Od Sitarjevca je ločeno z nad 300 m široko cono, v kateri doslej nismo našli pomembnejših rudnih pojavov. Osnova rudišča je zgrajena iz mladopaleozojskega kremenovega peščenjaka in konglomerata ter glinastega skrilavca. Na tem območju so jamska dela starega rudnika, ki je nehal obratovati 1.1855 in ga je zalila voda. L. 1959 sta si po predhodnem izčrpavanju vode in raziskovalnih delih na nivojih +212 m in +185 m ogledala dostopni del rudišča Jože Duhovnik in Franc Drovenik. Obstajajo pa tudi dobre stare jamske karte. Rudišče tvori v glavnem galenitno-sfaleritno-baritna žila s smerjo WNW—ESE in strmim vpadom proti NNE. Debelina te žile, ki vsebuje tudi kremen in kalcit, redko pa še pirit in halkopirit, znaša 10 do 30 cm, povprečno pa 15 cm. Zunanji, sfaleritni deli žil kažejo na največjo relativno starost tega minerala. Proti globini se sfalerit razpršuje, mineralizacija izgublja značaj žile in dobiva obliko impregnacij. Na nekaterih krajih doseže debelina orudene cone z impregnacijami vred tudi do 5 m. Vsebina Pb se z globino zmanjšuje, barit in kalcit pa se izgubljata. Rudišče je nad nivojem +212 m v glavnem odkopano. S svincem bogati deli so verjetno odkopani tudi niže, do nivoja +193,5 m. Ostafe ruda je relativno siromašna s Pb in vsebuje več Zn, po oceni Duhovnika in Drovenika povprečno 0,7 °/o Pb in 3 °/o Zn v odkopnih blokih debeline 1 m. Striglavec. Med znanimi nahajališči barita v širši okolici Litije so pojavi v dolini potoka Striglavec med najvzhodnejšimi. Osnovo tega območja tvori mladopaleozojski kremenov peščenjak. Vmes so ponekod tudi plasti temnega glinastega skrilavca. Na območju Štriglavca je več starih rudarskih del in odvalov. Na nekaterih najdemo kose rude, ki vsebuje sfalerit, galenit in barit. Barit se pojavlja le v severnem delu območja Štriglavca. Velike kose barita najdemo na odvalu rova, zgrajenega v kremenovem peščenjaku na višini približno +350 m desno od potoka. Vmes najdemo tudi galenit m sfalerit. Proti vzhodu spremljamo baritne pojave na severnem pobočju Velike njive, kjer je C i g 1 a r (1962) našel v potokih kose barita z gale^ nitom. Baritna cona se vleče tudi proti zahodu, kjer je izdanek barita severozahodno od Ognjičarja. Ta izdanek so leta 1959 podkopali z rovom. Njegov odval vsebuje kose kremenovega peščenjaka, vmes pa tudi precej barita z galenitnimi impregnacijami. Hrastarija. Več rovov z baritom in galenitom na odvalih je v jarku Popilovna in ob potoku Hrastarija. Ti pojavi so verjetno podaljški baritno-galenitnih rudnih žil, znanih iz Štriglavca in Pasjeka na vzhodu. Mamolj, Pasjek. Večina doslej opisanih del in izdankov vzhodno od Litije je razporejenih po severnih pobočjih Mamolja. Sem spadajo dela pod Sv. Janezom, v Štriglavem jarku, Hrastariji in ob zahodnem delu Polšenskega potoka. Pojavi rude na območju zadnjih dveh potokov so često opisani tudi pod imenom Pasjek. Vrbetov jarek. Med Spodnjim logom in Maljekom je baritni izdanek ob poti v Vrbetovem jarku. Maljek. Na območju potoka Maljek so sledovi zelo intenzivnega rudarjenja. Rovi so bili usmerjeni iz doline potoka pod hribe Špilj, Gradišče, Srednji hrib in Tri hraste. Ta rudarska dela so sekala in spremljala pretežno svinčeve in cinkove rudne žile. Tornquist (1929) je zapisal, da plasti peščenjaka in skrilavca vpadajo proti severu, žile pa imajo smer NW—SE. Rudni pojavi nastopajo približno 1 km od Maljeka. Na tem območju je po Tornquistu 12 rudnih žil; severnejše so bogatejše kot južnejše. S starimi deli so izkoriščali le sorazmerno plitva območja nad okolnimi dolinami. Globlji deli so verjetno nedotaknjeni. Leta 1930 so 300 m vzhodno od ustja potoka Maljek na višini 8 m nad Savo začeli kopati rov v smeri 165° 30' z namenom, da podkopljejo vse rudne žile tega rudonosnega pasu do Jablanice. Na 50 m rova so naleteli na 20 cm debelo žilo sfalerita, kmalu nato so prišli do prelomne cone s smerjo 65® in vpadom proti SE. Baritno žilo, debelo 15 cm, so našli v zgornjem, Svetlinovem rovu na drugem križišču. Koščke barita, galenita in sfalerita pa najdemo razen v Hrastovem potoku po vsej poti skozi Bukov graben. Baritna žila, ki prihaja na površino na vrhu hriba Spilje, ima smer SE—NW, vpada proti NE pod kotom 60° in je po Pastorju (1953) debela 80 cm. Na jezeh. Stari rovi in nasipi z galenitom in baritom na območju vzhodno od Samčeve žage pričajo o intenzivnem rudarjenju v preteklosti. Na grebenu, ki vodi proti SE, nastopa mineralizacija z galenitom in baritom v karbonskem peščenjaku in konglomeratu vzdolž prelomov povečini s smerjo 20 do 30°. Po Duhovniku (1947) znaša debelina rudnih žil, glede na kose v potoku, največ 90 cm. V njih je 2 do 3 °/o, največ 5°/oPb. Avtor pa ne omenja, ali je v rudnih žilah poleg galenita samo barit ali nastopajo v večjih količinah še drugi minerali. Zagorica. V Zagorici so stara rudarska dela razporejena na pobočjih štirih dolin: Velika dolina nad Kokolom, Šimenčkova dolina nad Pla-ninškom, Slatenska dolina nad 2ago in Ojstermanova dolina nad Jezom. Na odvalih najdemo barit in galenit. Na robu pobočja med Šimenčkovim in Slatenskim potokom je v zrušenem rovu izdanek barita. Obstajajo podatki o 4 rudnih žilah s smerjo 273° do 310° in z vpadi 28° do 805 proti NE. Le ena vpada pod 50° proti SW. Sitarjevec. Gozdnat hrib Sitarjevec južno od Litije je zgrajen iz mlajšepaleozojskega sljudnatega kremenovega peščenjaka, temnega glinastega skrilavca in bolj redko iz kremenovega konglomerata. Skrilavci in peščenjaki se pogosto pojavljajo izmenoma v tanjših ali debelejših plasteh. Na območju jamskih del Sitarjevca vpadajo plasti generalno proti W pod koti 25° do 45°, rudne žile pa imajo- smer NW—SE in vpadajo v glavnem proti NE. Rudne žile so zapolnitve predrudnih razpok. Postrudna tektonika je intenzivnejša. Izraziti so postrudni prelomi smeri SW—NE. Rudišče je snop več kot 40 rudnih žil in žilic, od katerih pa je le okoli 30 °/o rentabilnih za odkopavanje. Žile so najčešče nagnjene pod kotom 40° do 50° proti NE; vsebujejo galenit in barit in imajo v sedaj znanih delih do 60 cm BaSOi in do 10 cm PbS. V prejšnjih časih pa so odkopavali tudi žile debeline nad 2 m, npr. žilo Alma. Če spremljamo parageneze najvidnejših mineralov od zgoraj navzdol, vidimo, da je v zgornjih delih cinabarit, ki običajno spremlja barit, z baritom pa nastopa tudi galenit. Niže se najprej počasi umika barit, nato pa še galenit. še preden se barit popolnoma umakne, nastopi sfalerit. Njegova koncentracija z globino na- rašča in preide v telesa, kjer popolnoma prevladuje. Z njim nastopa kremen, ki ga končno v globini zamenja, tako da rudišče preide v jalove krem eno ve korene. Večje žile so v Sitarjevcu sledili z rudarskimi deli po vpadu 100 m do 150 m v višinskih intervalih 50 m do 100 m, vendar v teh intervalih v nobeni žili nismo mogli spremljati vsega prehoda od naj plitvejših do najglobljih paragenez po podani shemi, ampak smo si lahko sliko o zaporedju paragenez ustvarili po opazovanjih posameznih delov rudnih žil v različnih lokalnostih. Proti jugovzhodu je sistem rudnih žil prekinjen s cono glinastega skrilavca. Sistem orudenelih razpok se ponovno pojavi na jugovzhodni strani te cone. To so v letu 1962 in 1963 pokazale tri globinske vrtine na območju Dobrave. S temi vrtinami smo presekali na 18 mestih rudne pojave, in sicer v intervalu -r235,60 m do +111,00 m; imajo torej višinsko amplitudo 174,60 m in so razporejena na razdalji prek 300 m. Kako daleč sega orudenenje iz opisanega smernega in globinskega intervala, bo treba še ugotoviti z nadaljnjimi raziskavami. Poleg opisanih nahajališč barita najdemo na istem območju od vzhoda proti zahodu še naslednje sorodne rudne pojave brez barita: Preska (Pb), Polšnik (Pb), Pusti malen (Pb), Grmada (Pb, Zn), Jablanske Laze, (Pb, Zn), Jablanica (Pb, Zn), Tenetiše (Pb), Breg (Pb), Grmača (Pb), Štan-garska Poljana (Pb), Kresniški vrh (Pb), Štanga (Pb), Gozd Reka (Pb, Hg), Jevnica (Pb, Zn), Prežganje (Pb) in Andrejevec (Pb). Ni podatkov o baritu severno od Save v širši okolici Litije, verjetno se tam ne pojavlja. Zaloge barita v Sloveniji Razlikujemo dva glavna tipa baritnih orudenenj, in sicer tip Pleše in litijski tip. Tip Pleše nastopa lečasto in je relativno čist, litijski tip pa ima žilne oblike z manj čistim baritom in s primesmi galenita in drugih mineralov. Litijski tip baritnih teles je bolj razširjen kot tip Pleše in je verjetno zastopan tudi na območju rudišča Pleše v karbonskem peščenjaku. Zato je litijski žilni baritno-galenitni tip rudnih teles za pridobivanje barita bolj pomemben kot tip Pleše. Nimamo še podatkov o ekonomski vrednosti barita v Karavankah in pod Mangartom. Tudi pomena baritnih nahajališč na območju St. Janž— Laško—Trbovlje sedaj še ne moremo oceniti. Seveda velja to prav tako za okolico Pleš in Litije, čeprav imamo o tem območju največ podatkov. Za zdaj smo ocenili zaloge barita le na območje Pleš in Litije; prikazali smo jih na 7. tabeli. Skoraj vse zaloge kategorije A so na starih baritnih odvalih na jugovzhodnem pobočju Sitarjevca, kjer so jih odlagali, ko so odkopavali svinčevo rudo, barita pa še niso izkoriščali. Skupne zaloge barita vseh kategorij znašajo sedaj v Litiji in Plešah 217 000 ton. Ta količina ni tako neznatna, kajti znaša skoraj 8 °/o zalog sedanjih rudnikov barita v Jugoslaviji. Zanimiva je primerjava slovenskih zalog barita z zalogami proizvajalcev te surovine v Jugoslaviji (8. tabela). ZALOGE BARITA V PLEŠAH IN LITIJI V ZAČETKU LETA 1964 7. tabela Kategorija zalog (v tonah) Stopnja I^zisČ6 '' ■' ■ ■ ■ ■ — - . - rflzi sledil os ti A B AfB C, A+B+Ci C2 A+B+Ci+C2 (A+B): (C1+C2) — 710 710 — 710 16000 16710 0,04 Litija ležišče 1511 2094 3605 16841 20446 50000 70446 0 05 halde 30000 — 30000 — 30000 — 30000 — Nahajališča v širši okolici Litije — — — _ _ lOOOOO 100000 0,00 Skupaj ležišča 1511 2804 4315 16841 21156 166000 187156 0 02 Skupaj halde 30000 — 30000 — 30000 — 30000 Ležišča + halde 31511 2804 34315 16841 51156 166000 217000 Opomba: Zaloge v Plešah ocenil Ciril Janželj. Zaloge v Litiji ocenil ing. Milan Fabjančič. Zaloge v širši okolici Litije ocenila ing. Jože Tiringer in ing. Boris Berce v začetku leta 1956. Pri teh zalogah se stanje od 1. 1956 do 1.1964 ni bistveno spremenilo. ZALOGE BARITA V JUGOSLAVIJI 8. tabela Ležišče Lokve Ričice Topusko Ljubovija Velika Kladuša Gornji Vakuf Kreševo 30000 51000 Skupaj Slovenija (brez odvalov) 81000 1511 Kategorija zalog (ton) B A+B Cj Ci Ci+C* 79000 79000 30000 8000 38000 90000 90000 91000 — 91000 28000 58000 56000 400000 456000 300000 300000 150000 150000 300000 29000 80000 221000 — 221000 21000 21000 — 100000 100000 375000 375000 — 400000 400000 922000 1003000 548000 1058000 1606000 2804 431H 16841 166000 182841 A+B+Ci+Cj> Stopnja - raziskanosti (A+B):(Ci+Ct) 117000 181000 514000 600000 301000 121000 775000 2609000 187156 2,08 0,99 0,13 1,00 0,36 0,21 0,93 0,62 0,02 Kljub znatnim zalogam barita nižjih kategorij v Sloveniji, vidimo po primerjavi stopnje raziskanosti, da so slovenska najdišča barita mnogo slabše raziskana kot je povprečje v Jugoslaviji in da je ta surovina v Sloveniji popolnoma zanemarjena. Zato so potrebna izdatna vlaganja v raziskave rudišč, ki vsebujejo tudi barit, da bi tako ustvarili možnosti za normalno proizvodnjo barita v Sloveniji. To tudi zato, ker je proizvodnja barita v osnovi tehnološko že organizirana v Litiji. Predvsem je potrebno prekategorizirati zaloge C2 v zaloge višjih kategorij. Čeprav litijski barit ni tako kvaliteten kot barit iz Pleš, za proizvodnjo baritnih cementov vendar ustreza brez flotacijske predelave. Tipični vzorec litijskega barita vsebuje: Takšna kemična sestava pa ne ustreza pogojem, ki jih postavljajo glavni porabniki barita pri nas in na zunanjem tržišču. Zato so v Litiji uvedli flotacijsko pridobivanje barita. Na ta način so zboljšali njegovo kakovost. Flotacijsko pridobljen barit je že v začetku proizvodnje vseboval: BaS04 SiOž MgCOs CaC03 SrS04 AI2O3 PbS Fe F 90,46 % 5,28 % 2,55 % 1,10 % 0,52 % 0,16% 0,15% 0,08 % 0,05 % 100,35 % BaS04 Si02 CaO+MgO 95 % do 98 % 3 % do 0,2 % 0,5 % do 0,1 % 0,5% do 0,1% Pb Fe Mn h2o 0,3% do 0,01% (povprečno 0,15) 0,003 % 6 % do 8 % Granulametrijsko sestavo flotacijskega barita kaže 9. tabela. GRANULAMETRIJSKA SESTAVA FLOTACIJSKEGA BARITA 9. tabela Frakcija s premerom zmc (v mikronih) Utežni odstotek 120 in več 90 do 120 60 do 90 40 do 60 40 in manj 0,0 do 1,3 0,5 do 10,0 4,7 do 16,5 10,5 do 19,0 44,0 do 80,0 Tudi ta barit še nima vseh lastnosti visokokvalitetnega barita, vendar ga je možno z nadaljnjimi postopki zboljšati. V ta namen ga je treba beliti, mleti do granulacije 40 mikronov, pa tudi 15 do 20 mikronov, izžgati flotacijski film, ki obdaja zrnca flotacijsko pridobljenega barita, odstraniti okside železa in druge škodljive primesi ter ga ustrezno pakirati. Te postopke bo treba v Litiji uvajati zaradi rentabilnosti obratovanja, kajti litijski rudnik bo lahko obstajal in proizvajal visokokvalitetni barit le v primeru, če bo proizvajal tudi cenejše barite, uporabne za barijeve cemente in za druge potrebe. Po podatkih o dosedanji proizvodnji svinca v Litiji sklepamo, da mora izkopnina pri sedanjih prodajnih in proizvodnih pogojih za svinec* vsebovati 4,2 0/o Pb, da bi bilo obratovanje ob izključnem izkoriščanju svinčeve rude rentabilno. Za rentabilno pridobivanje barita brez svinca pa je za cenejše vrste barita potrebna izkopnina s 50 u/o BaSC>4, za dražje pa s 40 °/o BaSC>4. Ti podatki kažejo, da proizvodnja posamezne mineralne surovine v Litiji, pa naj gre za svinec ali barit, pri sedanjih zalogah v jami ne bi bila rentabilna. Tudi če bi poleg svinca proizvajali še nizkokvalitetni barit, ne bi dosegli rentabilnosti. Le skupna proizvodnja svinca in visokokvalitetnega barita bi bila rentabilna; pri tem bi bilo možno proizvajati vzporedno tudi cenejši barit za cementno industrijo. Po kratkem pregledu o stanju surovinske osnove lahko rečemo, da je iz kompleksne litijske rude možno rentabilno pridobivati barit, ker je med rudnimi zalogami 100 000 ton rudnih odvalov, pri katerih jamski stroški odpadejo. Vendar je osnovna proizvodnja rude v jami; tu pa so rudne zaloge višjih kategorij skoraj izčrpane. Do nedavnega tudi zaloge nižjih kategorij niso bile znane. Z raziskavami geološkega oddelka rudnika Mežica po letu 1963 pa so se zaloge nižjih kategorij povečale. Vendar zaradi pomanjkanja sredstev in težav pri izboljševanju tehnološkega postopka pri proizvodnji raziskovalna dela le počasi napredujejo. Da bi povečali proizvodnjo barita in svinca v Litiji, bi morali predvsem vlagati več sredstev v raziskovalna dela. Problematika geoloških raziskovanj baritnih nahajališč Čeprav lahko računamo v Sloveniji še z določenimi zalogami barita brez znatnejših primesi drugih mineralov, je glavni del zalog barita v kompleksnih rudah, ki vsebujejo poleg barita tudi galenit, cinabarit in cinkovo svetlico. Vsi ti minerali dosežejo na posameznih območjih pomembno koncentracijo tudi kot posamezne rudne1 komponente. Med nahajališči baritno-svinčevo-cinkovih in sorodnih rud v SlofVeniji so rudišča, v katerih se poj avlja barit v pomembnejših količinah, v manjšini. Vendar nam izkušnje kažejo, da so rudne žile, ki vsebujejo tudi barit, med vsemi rudnimi pojavi v Posavskih gubah * Cena 250 000,00 S-din/t rafiniranega svinca, 4000,00 S-din/t rude, 3000,00 S-din stroškov za predelavo 11 rude v izbiralnici, izkoristek v izbiralnici 90 v topilnici 95 %, topilniški stroški 30 000,00 S-din na 11 koncentrata z vsebino 65 % Pb. Letni obseg proizvodnje 20 000 ton rude. najbolj stalne in zato najpomembnejše. Zato je smotrno, da damo pri bodočih raziskovalnih delih na tem območju prednost prav galenitno-baritnim orudenenjem v predrudnih, morda ponekod tudi medrudnih razpokah s prevladujočo smerjo NW—SE. Po Tornquistovi teoriji naj bi bila najbogatejša rudna telesa v Posavskih gubah interstratificirane rudne plasti, podobno kot pri Pb-Zn ležiščih v Karavankah. Novejše raziskave pa so pokazale, da gre v Posavskih gubah za diskordantna rudna telesa, kar postavlja raziskovalna dela na bistveno drugačno osnovo. Dokaz za to nam nudijo zlasti opazovanja v Litiji. Osnovni kriterij pri usmerjevanju raziskovalnih del torej ni ožja stratigrafska opredelitev rudonosnega horizonta, ampak predvsem smer predrudne disjunktivne tektonike na območju nekdanjih emanacijskih centrov rudonosnih raztopin. Kljub temu pa imajo z baritom orudeneli prostori v Posavskih gubah tudi svoje stratigrafske meje. Na Slovenskem ni bil doslej v terciarnih sedimentih najden noben pojav niti baritne rude niti drugih rud z barit-nega kompleksa. V triadnih plasteh v Posavskih gubah se pojavljajo svinčevo-cinkove rude (Stranje, Ledina, Mokronog), medtem ko se baritna orudenenja ne oddaljujejo od kontakta mlajši paleozoik-triada v smeri stratigrafsko mlajših plasti. V glavnem pa se telesa svinčevih, cinkovih, bakrovih, antimonovih, živosrebrovih rud in barita pojavljajo v paleozoj-skih plasteh. To kaže na mladopaleozojsko in delno še starotriadno starost rudotvornih procesov na tem območju. Sklepamo, da je spodnji del werfena zgornja meja kompleksnih rudišč s pomembnejšo koncentracijo barita na območju Posavskih gub. Kazen diskordantnega položaja rudnih žil baritnega kompleksa, kaže na hitrotermalni nastanek še conama tekstura rudnih žil, pri čemer so vsokotemperaturni minerali (npr. ZnS) koncentrirani ob mejnih površinah in spodnjih delih žil, nizkotemperaturni minerali pa v srednjih in zgornjih delih žil (HgS). Barit in galenit sestavljata zgornje in osrednje dele rudnih žil. Zato je raziskovanje na območju baritnih in baritno-galenitnih izdankov ugodno, ker lahko pod njimi pričakujemo še obsežne dele rudnih žil, ki se raztezajo v globino. Upoštevati pa je treba, da so rudne žile pogosto prekinjene s prelomi, kar otežuje raziskovalno delo in odkopa-vanje. Ob nastajanju baritnih ležišč verjetno ni bil povsod prisoten triadni pokrov, ki je, kot kaže, imel s svojimi karbonatnimi plastmi določen vpliv na rudotvorni proces. Kjer so rudonosne hidrotermalne vode dosegle karbonatne kamenine, je prišlo v njih do intenzivnejšega odlaganja BaS04 ob delnem razvoju metasomatskega procesa. Takšen primer imamo v Plešah. Nadaljnje raziskave bodo morale pokazati, če je to povzročilo dekoncentracijo barita v nižjih paleozojskih klastičnih kameninah, kjer so se v razpokah usedali galenit, sfalerit in drugi minerali. Na območjih, kjer ni bilo triadnega pokrova, je barit v paleozojskih kameninah izdatno zastopan. Do podobnih ugotovitev je namreč prišel tudi J e r e m i č v Veliki Kladuši in drugod, da se barit pojavlja v glavnem v karbonatnih kameninah in le v primerih, če teh ni, je koncentriran v grobo klastičnih sedimentih. Med bosanskimi paleozojskimi baritnimi ležišči jih je 60 °/o v karbonatnih kameninah (apnenec, dolomit, marmor), 30 °/o v grobo klastičnih sedimentih (peščenjak, konglomerat, breča) in 10 °/o v glinastem skrilavcu. V Bosni so torej karbonatne kamenine imele pri rudotvornih procesih vlogo koncentratorjev rudnih substanc in zato tam nastopajo relativno bogatejša baritna rudna telesa. Na območju Posavskih gub pa so med mladopaleozojskimi plastmi karbonatne kamenine samo izjemno zastopane. Zato pri nas v paleozoiku ni prišlo do nastanka velikih metasomatskih rudnih teles. Na karbonatne kamenine so baritonosne terme naletele le v spodnjem delu werfena, kjer je obstajal. Zadnja baritna telesa so nastajala v spodnjem delu triade, na kar kaže položaj baritnih leč v Plešah. Zato pozneje ni moglo priti do metasomatskih koncentracij barita v mlajših karbonatnih kameninah. V naših rudnih žilah v paleozoj-skih plasteh pa so se koncentrirali poleg barita tudi drugi koristni minerali, zlasti galenit in sfalerit, kar povečuje vrednost teh rudišč. Orudene-nja v triadnih plasteh, med katerimi ni več barita, so le rudne tvorbe posthumnih triadnih emanacij. Vprašanje raztezanja baritno-galenitno-sfaleritnih žil v globino za sedaj še ni rešeno. Vsekakor pa lahko pričakujemo, da dosegajo večje globine, kot so običajno smatrali nekateri geologi in rudarji, ki so razpravljali, ali je verjetno, da segajo v Litiji rudna telesa pod savsko obzorje ( + 248) ali ne. Danes vemo, da tudi baritna rudna telesa segajo pod današnje najnižje obzorje +192 m. kar govori še za znatne globine baritno-svinčevega, svinčevo-cinkovega in cinkovega globinskega intervala. Z globinsko vrtino št. 5 v Dobravi smo na sledove PbS in BaS04 naleteli še na nadmorski višini + 111 m. Metoda raziskovanj z globinskim vrtanjem se je pokazala pri raziskovanju kompleksnih rudnih žil v okolici Litije kot zelo uspešna. Dala je hitre in zanesljive rezultate o orudenih območjih. Zato bi jo morali tudi v bodoče uporabljati. Geološke raziskave naj bi bile usmerjene k določanju ožjih orudenih območij za raziskovanje z globinskim vrtanjem. Pri tem delu bi uporabljali tudi pomožne raziskovalne metode geofizike, geokemije in druge. Prednost bi bilo treba dati tistim območjem, v katerih bi mogli zaradi ugodnih pogojev novoodkrite zaloge kmalu odkopavati. Takšni pogoji so predvsem v okolici Litije. S tem bi omogočili, da bi rudnik Litija postopno povečal proizvodnjo barita in svinca, pa tudi cinka. Pri jamski rudarski eksploataciji so ob zadovoljivih hidrogeoloških pogojih najboljše možnosti za doseganje dobrih ekonomskih rezultatov do globin 300 ali 400 m pod površino (J a n k o v i č , 1960). Zato je treba raziskave z globinskim vrtanjem omejiti na globino do 300 m. Večji del tega območja je v Posavskih gubah čista celina, v kateri ni bilo še niti raziskav niti eksploatacije, kljub geološkim pogojem za odkrivanje novih, predvsem baritno-svinčevo-cinkovih orudenenj. Zato bi bilo treba vlagati v te raziskave znatna sredstva ob sodelovanju podjetij, ki so zainteresirana za barit ter svinčev in cinkov koncentrat. ABOUT BARITE OCCURRENCES IN SLOVENIA This assay gives a survey of barite occurrences in Slovenia and adds them their economic dimension from the aspect of production and uses of barite in technic and industry as well as the turnover of this mineral matter to the world extent. Thus proportions for valuation of the significance of production, domestic consumption and export of Yugoslave barites are created and a statement is made that Yugoslavia is one of the ten greatest world producers of barite. The author deals with the possibilities of discovering new barite ore reserves in Slovenia. On this area two barite mines, Pleše and Litija have been active. The concentration of BaS04 in Pleše barite (93 °/o to 99 °/o) was higher than in that of Litija (88 °/o to 95 %>) and therefore the quality of the first one is considerably better. By processing and other improving operations also from the Litija lead-zinc-barite complex ores barite products of high grade quality can be gained. On such principles the new introduced production of barite is developing in Litija, which is by now the single active barite mine in Slovenia. However, the assurance of exploatable barite containing ores becomes a burning question. In Slovenia the following barite occurences are known: Sancetova ruda, Odanče, Belščica, Počivalnik, Dule, Pleše, Vrhovka, Šmarje, Volčja jama, Probsov kamnolom, Arhov graben, Zavrstnik, Sitarjevec (the mine Litija), Dobrava, Zagorica, Na jezeh, Maljek, Vrbetov jarek, Podčešje, Hrastarija, Mamolj, Pasjek, Striglavec, Marija Reka, Podkraj, Brezno, Budna vas, Lokavec, and Ples. Most of these locations are scattered in tectonic unity of Sava folds on the area of the Litija anticline. There are two main types of barite deposits in Slovenia: the Pleše-and the Litija-type. The significance of the first of them is more or less regular lense form of ore bodies and relative purity of barite substance. The widely prevailing Litija-type appears in the form of veins containing chiefly galena, sphalerite, and barite. Total reserves of barite in Slovenia amount for the time being to 217 000 tons. The major part of them are complex galena-sphalerite-barite ores. In the lead, zinc, and barite concentrates, which can be produced by mines on the area of Slovene barite deposites, many enterprises are interested. By this proceedings preferance should be given to the exploration works with the purpose of increasing of ore reserves. In complex ore bodies containing barite, galena, sphalerite, cinnabar, and copper ores, also single of these minerals attain economic concentrations on particular locations, but the veins with presence of barite show the greatest permanence and owing to a usually considerable content of galena they are the most important kind of ore types appearing on the area of Sava folds. Although barite-galena veins are joined on preore fissures, the spaces containing ore appearances also have their stratigraphic limits. In any case the upper stratigraphic limit of barite appearances on the area of Sava folds is not removed far from the contact Younger Paleozoic-Triassic in the direction to stratigraphicaly younger strata. This is evident by geological situation of the Pleše barite deposit. In the majority barite-galena deposits appear in Paleozoic strata, accompanied by other mineralisations. They are doubtless of hydrothermal origin and surely of Younger Paleozoic till Lower Triassic age. During formation of barite deposits the Triassic cover was probably not present in all the parts where they arose. Where it was, the cover had a certain modifying influence on ore-forming processes, owing to its carbonate strata (limestones, dolomits). Where the ore-bearing hydro-thermal solutions arrived to carbonate rocks, an intensive deposition of BaSC>4 and the simultaneous partial replacement took place. Such a case is observed in Pleše. On the places where Triassic cover was absent during the ore-forming process, barite was deposited in Paleozoic rocks. In Paleozoic of Sava folds the carbonate rocks occur only exeptionally. For that reason in Slovenia opulent metasomatic barite bodies appear rarely. Instead of this in ore-veins in Paleozoic rocks next to barite particularly galena and sphalerite were concentrated, which increases the walue of these barite deposits. The problem of continuation of barite-galena-sphalerite veins into the depth has not been solved yet. By the drill-holes in Dobrava near Litija the traces of PbS and BaS04 were found still on the plus 111 m level. Future geological explorations should be directed to limiting of ore bearing zones interesting for further exploration by drilling and mining works. By previous drillig in Dobrava good results were obtained. Priority should be given to those locations, where the technical conditions allow prompt beginning of exploitation of new ore reserves. Such conditions are realized in the surroundings of Litija. By explorations cm. this area the increase of output of barite, lead and zinc in Litija mine should be made possible, while in perspective in the wide region of Sava folds new mining centres for production of these raw materials should be organized. Finally, the exploration as well as the exploitation would not be performed without difficulties, due to contorted ore- bearing strata and interrupted ore veins. LITERATURA Dammer, B. in Tietze, O., 1914, Die nutzbare Mineralien, Band II, Stuttgart. Tornquist, A., 1929, Die Bled- Zinkerzlagerstatte der Savefalten voim Typus Litija, Wien. Tilli, H. J., 1951, Scraper Assembly Cuts Costs at Open-Pit Barite Mine. Engeneering and Mining Journal, vol. 152, Number 3, New York. Jelene, D., 1953, O raziskovanju mineralnih surovin v LR Sloveniji. Geologija, 1. knjiga, Ljubljana. Johnstone, S. J., 1954, Minerals for the Chemical and Alied Industries, London. Zebre, S., 1955, Rudarska dejavnost v območju posavskih gub. Rudarsko-metalurški zbornik, št. 4, Ljubljana. B r o n i s k i, A., 1957, Barium- und Strontium- Zemente. Zement — Kalk — Gips, Heft 5, Wiesbaden. Gomišček, S., 1957, Prispevek k polarografskemu določevanju svinca v baritnih rudah in njih flotacijskih produktih. Rudarsko-metalurški zbornik, št. 2, Ljubljana. J u r k o v i č, I., 1957, Metalogenija Petrove gore u jugozapadnoj Hrvatsko j (Habilitacijona radnja). Geološki vjesnik XI, Zagreb. C i č i č, S., 1957, Geologija ležišta barita na Podkovaču severna Črna Gora. Geološki glasnik, Sarajevo. Jeremič, M., 1958, Baritska ležišta Jugoslavije i mogučnosti njihovog razvoja. Tehnika br. 3, Beograd. O n i č, D., 1958, Eksploatacija barita na području Lokve—Mrzle vodice. Nemetali 1, Zagreb. Jeremič, M., 1958, Baritno-fluoritno ležište »Zune« kot Ljubije. Rudarsko-metalurški zbornik, št. 4, Ljubljana. Peters, W. C., 1D58, Economic position of Western Barite Deposits. Mining engineering, vol. 10, No. 9, New York. Jurkovič, I., 1958. Pojave barita u Hrvatskoj. Geološki vjesnik XII, Zagreb, Jakžin, A. A., 1959, Poiski i razvedka mestoroždenij poleznyh iskopaemyh, Moskva. U. S. Department of the interior, Bureau of mines, Minerals Yearbook 1959. Jeremič, M., 1960, Intenzitet i ekstenzitet bosanske hidrotermalne bariti-zacije. Rudairsko^metalurški zbornik, št. 2, Ljubljana. Jeremič, M., 1960, Baritonosno područje Une i Sane u sjeverozapadnoj Bosni. Tehnika br. 2, Beograd. Broniski, A. in Ionescu, 1960, Bariumoxydhaltige feuerfeste Tonerde-zemente. Zement-Kalk-Gips, Heft 3, Weisbaden. Jan kovic, S., 1960, Ekonomska geologija, Beograd. Jurkovič, I., 1961, Istraživanja rudnih ležišta u N. R. Hrvatskoj. Geološki vjesnik 15, Zagreb. Broniski, A., 1961, Ahnlichkeiten und Verschiedenheiten der Calcium-, Strontium- und Barium-Zemente. Zement-Kalk-Gips, Heft 1, Wiesbaden. Jeremič, M., 1962, Pojava barita kod Jerme u Istočnoj Srbiji. Rudarsko^ metalurški zbornik, št 1, Ljubljana. Jeremič, M., 1962, Mogučnost koriščenja barita iz olovo-cinkanih ležišta Zletovo u Makedoniji. Tehnika, br. 11, Beograd. Grafenauer, S., 1963, O mineralnih paragenezah Litije in drugih poli-metalnih nahajališč v posavskih gubah. Rudarsktometalurški zbornik, št. 3, Ljubljana. Jeremič, M., 1963, Koeficient zaobljenosti baritndh valutica kao mjerilo rastojanja od primarnih do predeponovanih baritnih ležišta, Tehnika 5, Beograd. Jeremič, M., 1963, Metalogenija paleozojskih ležišta barita Bosne. Arhiv za tehnologiju, 1-2, Tuzla. Arhiv Geološkega zavoda v Ljubljani, rudnika Litija in bivše uprave Posavskih rudnikov svinca in barita v Ljubljani. RAZVOJ SFODNJEKREDNIH SKLADOV TER MEJA MED JURO IN KREDO V ZAHODNEM DELU TRNOVSKEGA GOZDA Dragica Turnšek in Stanko Buser Z 1 sliko med tekstom in s 3 tablami slik v prilogi Uvod Na podlagi mikrop ale ontološki h raziskav nam je na Trnovskem gozdu uspelo razčleniti zgornjejurske in spodnjekredne sklade na več horizontov. Zato v tem članku uvajamo v slovensko geološko literaturo nova imena za posamezne geološke stopnje. Da bi poenotili slovensko stratigrafsko nomenklaturo, smo nekoliko spremenili tudi dosedanje nazive posameznih stopenj. Podobno kot je Pavlovec za paleogenske stopnje uvedel izraze z enotnimi končnicami na i j, bomo imenovali tudi stopnje jurskih in spodnjekrednih skladov enotno. V 1. tabeli podajamo imena stopenj za zgornjo juro in spodnjo kredo, za primerjavo pa še angleške, francoske in italijanske izraze. ZGORNJEJURSKE IN SPODNJEKREDNE STOPNJE UPPER JURASSIC AND LOWER CRETACEOUS STAGES 1. tabela Table 1 Lower Cretaceous Spodnja kreda Slovensko albij aptij barremij hauterivij valanganij Angleško Albian Aptian Barremian ttauterlvian Valanginian Francosko albien aptien barremien hauterivien valanginien Italijansko albiano aptiano barremian o hauteriviaino valanginiano y 'to P* portlandij Portland ian portlandien portlandiano 3 kiimmeridgij Kimmerldgian kimmeridgien kimmeriidgiano & ft oxford i j Oxford i an oxfordien oxfordiano a D U N Terenske raziskave V zadnjih letih smo kartirali območje osnovne geološke karte lista Gorica. Pri kartiranju nam je uspelo rešiti nekatere zanimive probleme, med drugim tudi vprašanje o meji med jurskimi in krednimi plastmi na zahodnem delu Trnovskega gozda. Jurske in kredne plasti na Trnovskem gozdu so znane že prek sto let. Precej podrobno jih je opisal Stur (1858). Kasnejši raziskovalci, posebno Hauer (1868), Kossmat (1905, 1906 in 1909), Winkler (1924), S t a c h e (1885 in 1920) in Wiontzek (1934) so se držali v glavnem njegovega mišljenja o starosti teh plasti. Na geoloških kartah (Kossmat, 1905 in S t ache, 1920) so na območju Trnovskega gozda zgornjejurski skladi razdeljeni na sferaktinijski in koralni apnenec ter nerinejski apnenec titonske stopnje. K spodnji kredi pa je prištet ozek pas plošča-stega trnovskega apnenca na zahodnem delu Trnovskega gozda. Na podlagi mikropaleontoloških raziskav smo dognali, da pripada večji del nerinejskega apnenca, ki so ga doslej prištevali izključno zgornji juri, spodnjemu delu krede, tj. valanginiju in hauteriviju. Skladi, ki pripadajo vrhnjemu delu malma, tj. zgornjemu kimme-ridgiju in portlandiju, se vlečejo v dveh ozkih pasovih vzhodno od Trnovega. Prvi pas poteka od južnega strmega roba Trnovskega gozda prek Krnice in naprej proti severu ter se zaključi ob prelomu južno od vasi Nemci. Drugi pas malmskih plasti poteka južno od vasi Rijavci proti severu in severovzhodno od vasi Voglarji preide na ozemlje sosednje, tolminske karte. Starost 2gornjemalmskih plasti je dokazana predvsem na podlagi mikroflorističnih ostankov. Da bi določili točno starost teh plasti, smo nabrali v vzporednih prečnih profilih precej vzorcev za mikropaleonto-loške raziskave (1. si.). V zbruskih apnenca smo našli številne primerke alge Clypeina jurassica Favre, ki jasno kažejo, da pripadajo ti skladi zgornjemu malmu. S tem je tudi dokazano, da so koralni in hidrozojski apnenci, ki leže pod skladi z algo Clypeina jurassica, starejši. Kossmat (1909, 91) jih je namreč primerjal s titonijskim štramberškim horizontom. V zgornjem delu zgornjemalmskih plasti se pojavljajo skupaj z algo Clypeina jurassica tudi velike tintinine. Debelina tega horizonta znaša 10 metrov. Ponekod postavljajo mejo med zgornjo juro in spodnjo kredo tam, kjer se pojavijo prvi primerki velikih tintinin. Na Trnovskem gozdu smo prišteli horizont, v katerem se pojavljajo Clypeina jurassica in tintinine skupaj, še titonu, in mejo med juro in valanginijem postavili tam, kjer alga Clypeina jurassica izumre. Upoštevamo namreč ugotovitve in mnenja večine raziskovalcev, da je ta alga vodilna za zgornji del malma in sega do meje jura-kreda. Po našem mnenju so se velike tintinine pojavile že proti koncu portlandija in niso vezane izključno na valanginij. Vsekakor pa je meja med portlandijem in valanginijem na Trnovskem gozdu postopna. V zgornjem delu zgornjega malma se pojavljajo tudi številne nerineje, po katerih je dobil ime nerinejski apnenec. Pri zadnjih raziskavah se je pokazalo, da segajo nerineje v zahodnem delu Trnovskega gozda še RAZLAGA TABEL — EXPLANATION OF PLATES 1. tabla — Plate 1 1. Odlomki alge Clypeina jurassica Favre, X 10. Zg. kimmeridgij-portlandij, zbrusek št. 3 b. The fragments loi Clypeina jurassica Favre, X 10. U. Kimmeridgian-Portlandian, thin section No. 3 b. 2. Odlomki velikih tintinin, X 10, valanginij, zbrusek št. 18 b. The fragments of large tintinins, X 10, Valanginian, thin section No. 18 b. 2. tabla — Plate 2 1. Cuneolina laurentii Sartoni e Crescenti, X 35, aptij (Aptian), zbrusek (thin section) 25 d. 2. Choffatella sp., X 35, valanginij (Valanginian), zbrusek 7. 3. Salpingoporella apenninica Sartoni e Crescenti, X 35, hauterivij (Hauterivian), zbrusek 22 c. 4. Favreina salevensis (Parejas), X 35, hauterivij (Hauterivian), zbrusek 8 a. 5. Haplophragmoides sp., X 35, barremij (Barremian), zbrusek 23 c. 6. Salpingoporella dinarica Radoičič, X 35, aptij (Aptian), zbrusek 28 c. 7. Solenopora sp., X 35, valanginij (Valanginian), zbrusek 6 c. 3. tabla — Plate 3 1. Orbitolina sp., X 19, aptij (Aptian), zbrusek (thin section) 30 b. 2. Trochamminoides sp., X 35, barremij (Barremian), zbrusek 23 c. 3. Bačinella irregularis Radoičič, X 35, barremij (Barremian), zbrusek 23 b. 4. Salpingoporella dinarica Radoičič, Cuneolina sp., X 35, aptij (Aptian), zbrusek 28 c. 3. TABLA PLATE 3 SI. 1. Najdišča vzorcev apnenca z mikrofosili v zahodnem detlu Trnovskega gozda Fig. 1. Localities of the limestone samples with micrcrfossils taken in the western part of Trnovski gozd v plasti, ki vsebujejo samo velike tintinine, in že nesporno pripadajo valanginiju. Nerineje paleontološko še niso raziskane. Zgornji del malmskih plasti je v zahodnem delu Trnovskega gozda razvit kot bel do rjavkasto siv in svetlo rjav gost skladovit apnenec. Med gostim apnencem se pojavljajo pole oolitnega apnenca. V spodnjem delu tega kompleksa leži pri Krnici in v okolici Rijavcev neskladovit bel zrnat dolomit, ki se bočno izklinjuje in zato ponekod sploh ni razvit. Clypeina jurassica se pojavlja v gostem in oclitnem apnencu, nerineje pa so številnejše v oolitnem apnencu. Zanimivo je, da je v vzhodnem delu Trnovskega gozda razvit v zgornjem delu malma bel zrnat dolomit, ki se horizontalno menjava s svetlim apnencem. Prav takšen je razvoj teh plasti na Hrušici ter na Logaški planoti in na Dolenjskem. Apnenec vsebuje klipeine, nikjer pa ne dobimo za zahodni del Trnovskega gozda tako značilnih nerinej. Na Trnovskem gozdu imamo torej dva razvoja zgornjemalmskih skladov, ki se ločita med seboj po litoloških in delno tudi po biostratigrafskih značilnostih. 34 — Geologija št. 9 529 Ta razlika se ne kaže samo v zgornjemalmskih skladih, ampak v celotnem razvoju jurskih plasti. Valanginijske plasti so litološko razvite popolnoma enako kot zgornje-malmske. Toda v njih nastopajo velike tintinine brez alge Clypeina juras-sica, dobimo pa številne druge alge. Celotna združba mikrofavne in mikroflore je vidna v paleontološkem delu iz posameznih profilov. Plasti hauterivijske stopnje zavzemajo večjo površino kot valanginij-ski in zgornjemalmski skladi. V njih nastopajo v glavnem iste vrste alg kot v valanginijskih plasteh, toda velikih tintinin ni več. Značilne za hauterivij so zelo pogostne favreine, ki sicer za stratigrafijo niso toliko uporabne. Važno pa je v tej spodnjekredni stopnji njihovo masovno pojavljanje. V hauterivijskih plasteh tudi ni več nerinej, ki so v valan-giniju še zelo pogostne. Velike tintinine in neiineje so izginile istočasno. Hauterivijske plasti so razvite v obliki belega gostega skladovitega apnenca. Le poredko se med gostim apnencem pojavijo do en meter debele pole oolitnega apnenca. Pri Trnovem in Voglarjih je razvit v zgornjem delu hauterivijske stopnje temno siv in črn ploščast apnenec, ki vsebuje gomolje roženca. Ne predstavlja sklenjenega horizonta, temveč se bočno izklinja. Šele ta apnenec, ki so ga prejšnji raziskovalci imenovali trnovski ploščasti apnenec, so prištevali v spodnjo kredo. Celoten kompleks skladov pod tem ploščastim apnencem, tj. ves valanginij in spodnji hauterivij, pa so uvrščali v zgornjo juro. Barremijskih in aptijskih skladov na terenu nismo ločili, ker so litološko enaki. Zavzemajo precej velik obseg med Trnovim in Podgozdom. Razviti so kot rjavkasto siv do temno siv precej bituminozen apnenec, ki se menjava z gostim belim apnencem. Pri Podgozdu nastopa v zgornjem delu teh skladov temno siv apnenčev skrilavec, ki je precej bituminozen ter vsebuje pole in gomolje roženca. Tudi horizont apnenčevega skrilavca se proti jugu izklini. Starost barremijsko-aptijskih skladov je določena z makrofavno in mikrofosili. Od makrofosilov vsebujejo Toucasia cf. carmata Math., Re-quienia ammonia Goldf. in Nerinea sp. Zahodno od Voglarjev dobimo tudi kaprinide in radiolite. Nekatere horizonte sestavljajo same zaobljene lupine omenjenih fosilov. Mikrofosili, ki se pojavljajo v teh plasteh, so navedeni v poglavju o mikropaleontoloških raziskavah (5. in 6. tabela). Albijsko stopnjo smo združili s cenomansko, ker v plasteh teh dveh stopenj nismo našli značilnih fosilov, da bi ju lahko ločili. Plasti teh dveh stopenj se razprostirajo na velikem območju zahodno od Trnovega in Podgozda. Enake plasti so razvite tudi na območju gora Sv. Gabrijel in Skalnica (Sv. gora) ter severnega dela Sabotina, kjer sestavljajo pre-vrnjeno antiklinalo. Starost teh plasti smo določili delno po fosilnih ostankih delno pa po njihovem stratigrafskem položaju. V njih se dobe številne lupine rekvienij in nerinej. V zbruskih smo dobili tudi orbitoline. Pri Mrzleku v dolini Soče ter na sedlu med Skalnico in Sv. Gabrijelom so bile najdene fosilne ribe, ki jih je zelo natančno obdelal Gorjanovič-Kram- berger (1895). V albijskih in cenomanskih plasteh nastopajo pogostni primerki velikih radiolitov. Albijski in cenomanski skladi so razviti v obliki temno sivega do rjavkasto sivega skladovitega apnenca, ki je navadno precej bituminozen. Ploščast apnenčev skrilavec z ostanki rib nastopa v srednjem delu teh skladov. Nad cenomanskimi skladi leži konkordantno bel zrnat radiolitni tu-ronski apnenec, ki vsebuje v spodnjem delu zelo značilen in stalen horizont s kaprinidami. Spodnjekredne kamenine so v Sloveniji mikropaleontološko še zelo malo raziskane. Doslej je bil z mikrofavno dokazan le valanginij na nekaterih krajih Dolenjske in Notranjske (Turnšek, 1964). Pleni č a r (1960) se je pri svojem obsežnem študiju kredne dobe posvetil predvsem zgornji kredi in raziskovanju rudistne favne. Mikropaleontološke raziskave spodnjekrednih skladov so dale v so-sosednjih republikah, pa tudi drugod po svetu, že lepe rezultate. Zato smo izdelali na Trnovskem gozdu natančen profil skozi zgornjemalmske in spodnjekredne sklade. Mikropaleontološke analize so omogočile, da smo v spodnji kredi lahko ločili več stratigrafskih stopenj: valanginij, haute-rivij, barremij, aptij ter albij. Naše delo je bilo toliko zanimivejše, ker smo rezultate lahko primerjali z razvojem v Dalmaciji, Orni gori in v južnih Apeninih. V najdiščih na Trnovskem gozdu je ta vrsta sorazmerno redka in slabo ohranjena. V zbruskih dobimo le odlomke stebelc. Našli smo jo v zgornjeportlandijskih in spodnjevalanginijskih plasteh v vzorcih 3, 4, 10, 18, 20 in 22. 1962, S. apenninica, Sartoni e Crescenti, pp. 266—268, Tav. 20, fig. 2, Tav. 23, fig. 1, Tav. 44, fig. 1, 2, 4, 5, 6, 8 Talus ali osrednja cevka je valjast, v prečnem preseku okrogel, z gladko steno. Verticili so pogostni in prekrivajo vso osrednjo cev. Vrsta S. apenninica je podobna vrsti S. annulata, le manjša je od nje in med posameznimi vretenci ima brazde. Mikropaleontološki del Al g a e Družina: DIPLOPORIDAE Rod: Salpingoporella Pla 1918 Salpingoporella annulata Carozzi Salpingoporella apenninica Sartoni e Crescents 2. tab., 3. si. Dimenzije naših primerkov po Crescentiju 1,39 mm 0,097 do 0,22 mm 0,19 do 0,32 mm največja dolžina steljke premer osrednje cevi premer steljke 0,8 mm 0,09 do 0,12 mm 0,25 do 0,30 mm Stratigrafska in regionalna razširjenost: Sartoni in Crescenti sta prvič opisala to vrsto iz južnih Apeninov iz okolice Salerna. Plasti s to algo sta imenovala »cona s Salpingoporella apenninica«. Dobila sta jo nad horizontom s tintininami, ki sta jih prištela med pteropode in jih po Carozziju imenovala Vaginella striata. Cono s Salpingoporella apenninica sta uvrstila v zgornji titomij, v spodnji titanij pa cono s Clypeina jurassica in Vaginella striata. Toda če upoštevamo ugotovitve večine mikropaleontologov, da je Clypeina jurassica značilna za ves zgornji malm (= zgornji kimmerdgij in portlandij), in da so velike tintinine značilne za valanginij (Radoičič, 1963), potem je cona s Salpingoporella apenninica mlajša od plasti z velikimi tintininami, vsekakor pa mlajša od zgornjega portlandija. Rod Salpingoporella se z nekaterimi vrstama res pojavlja v zgornji juri, ne more nam pa rabiti pri razmejevanju jure in krede, ker se iste vrste pojavljajo še v spodnji kredi. Na Trnovskem gozdu smo dobili vrsto S. apenninica skupaj z velikimi tintininami in v plasteh nad njimi, tj. v valanginiju in hauteriviju. V Sloveniji je znana le s Trnovskega gozda, verjetno pa se pojavlja povsod, kjer poznamo podoben razvoj skladov, le da smo jo zaradi izredne podobnosti z vrsto S. annulata prezrli ali uvrščali k tej vrsti. Vrsto S. apenninica smo dobili v vzorcih 10, 20 in 22. Salpingoporella dinarica Radoičič 2. tab., 6. si., 3. tab., 4. si. 1959, S. dinarica, Radoičič, pp. 33, Tab. 3-4 1959, S. dinarica, Radoičič, Tab. 8, si. 2 1960, S. dinarica, Radoičič, Tab. 15, si. 1, 2, tab. 16, si. 3, tab. 17, si. 2 1962, S. dinarica, Sartoni e Crescenti, pp. 268, Tav. 27-28, Tav. 45, fig. 1-3 Steljka je cilindrična. Osrednja cev je sorazmerno velika. Obdajajo jo majhni gosti izrastki, ki so v dveh sosednjih vretencih razporejeni diagonalno. Naši primerki popolnoma ustrezajo opisom Radoičičeve, samo da so nekateri manjši. Dimenzije naših primerkov po Radoičičevi premer steljke 0,13 do 0,49 mm 0,24 do 0,56 mm premer osrednje cevi 0,07 do 0,26 mm 0,128 do 0,40 mm Razširjenost: Vrsto S. dinarica je prvič opisala Radoičičeva (1959) iz okolice Titograda in iz raznih krajev južne Dalmacije. Našla jo je v barremijsko-aptijskih skladih. Danes je ista avtorica mnenja, da je vrsta S. dinarica vodilna za aptijsko stopnjo. Italijanska raziskovalca Sartoni in Crescenti sta vrsto S. dinarica dobila v zgornjem delu cone s Cuneolina composaurii (valanginij—aptij) torej približno1 v istem horizontu kot v Dalmaciji in v Črni gori. K tej vrsti sta prištela tudi primerek, ki ga je Elliott opisal pod imenom Hensonella cylin-drica n. gen. n. sp. iz barremijsko-aptijskih plasti v Iraku (Sartoni e Crescenti, 1962). V Sloveniji smo vrsto S. dinarica našli doslej le v vzorcih 28, 30 in 31 s Trnovskega gozda in smo sklade s to algo uvrstili v aptij. Rod: Clypeina Michelin Clypeina jurassica Favre 1. tab., 1. si. Alga .C. jurassica je bila podrobno opisana že iz raznih krajev Notranjske in Dolenjske (K e r č m a r , 1962). Na Trnovskem gozdu jo nahajamo v skladih zgornjekimmeridgijske in portlandijske starosti nad apnenci s hidrozoji. Dobili smo jo v vzorcih 1 do 5 in 17. ? Tintinnina Velike tintinine 1. tab., 2. si. Fosilne oblike, ki jih je Favre označil kot organizem »C«, in ki jih je Carozzi pozneje imel za pteropode ter jih imenoval Vaginella striata n. sp. (Carozzi, 1954), je Radoičičeva uvrstila med ciliata k tintininam (Radoičič, 1959, 1963). F a r i n a c c i pa jih je določila za školjke skupine Teredinidae. Vse primerke je dala v eno vrsto Bankia striata (Carozzi). Pri tem je opozorila, da reduplikacija, ki se pojavlja pri tem organizmu, pni ciliatih doslej ni znana. Poleg tega je ugotovila, da imajo stene teh fosilnih fragmentov dve plasti, sestavljeni iz sorazmerno velikih nepravilnih kalcitnih kristalov, medtem ko imajo fosilne tintinine mikrokristalne kalcitne stene (Farinacci, 1963). Od številnih primerkov, ki smo jih opazovali, imajo dvojne stene samo tiste oblike, pri katerih nastopa reduplikacija. Pni številnih enojnih oblikah so tudi stene enojne in pri teh ne moremo govoriti o stenah iz več plasti. Reduplikacija pa je pri školjkah ravno tako posebnost kot pri tintininah. Zato še naprej upoštevamo mišljenje Radoičičeve in problematične oblike uvrščamo k tintininam, dokler njihov sistematski položaj ne bo preučen. Na Trnovskem gozdu so velike tintinine slabše ohranjene kot v nekaterih najdiščih Dolenjske in Notranjske. Določili smo lahko naslednje vrste: Campbelliella mileH Radoičič Cam-pbelliella sp. Daturellina costata Radoičič Zetella sp. Vse te vrste so opisane že iz najdišč na Dolenjskem (T u r n š e k , 1964), zato jih s Trnovskega gozda omenjamo samo kot novo najdišče. Velike tintinine tudi na Trnovskem gozdu nastopajo v zgornjem portlandiju skupaj z algo Clypeina jurassica, številnejše pa so v valan-giniju, kjer jih spremljajo redke salpingoporele. Velike tintinine smo našli v vzorcih 4 in 5, 6 in 7, ter 17. do 20. Foraminifera Družina: VERNEUILINIDAE Vemeuilina sp. Hišica je triserialna, navadno trioglata. V zbruskih dobimo številne preseke, značilne za rod Vemeuilina. Nekateri primerki so tudi izredno lepo ohranjeni, toda zaradi pomanjkanja literature vrste nismo mogli determinirati. Različne verneuiline smo našli v hauterivijskih, barremijskih in aptijskih skladih v vzorcih 21, 23, 28 in 29, Cuneolina laurentii Sartoni e Crescent! 2. tab., 1. si. 1962, C. laurentii, Sartoni e Crescenti, pp. 277-278, Tav. 48. fig. 7-9, tav. 49. fig. 1 V zbruskih dobimo longitudinalne aksialne preseke, ki ustrezajo prvim opisom te vrste. Hišica je koničasta, nekoliko stisnjena. Kamrice se večajo od baze proti vrhu. Razširjenost: Holotip je opisan iz Monte Alburno v južnih Apeninih. Več primerkov je najdenih še v raznih drugih okoliških krajih. Sartoni in Crescenti ga omenjata v coni s Cuneolina corriposaurii (valanginij-aptij). Na Trnovskem gozdu nastopa ta vrsta v spodnjem delu aptija skupaj z algo Salpingoporella dinarica. Dobili smo jo v zbruskih 25 d in 28 c. Cuneolina sp. 3. tab., 4. si. Nekateri primerki so slabo ohranjeni ali pa je v zbrusku tako slab presek, da vrste ne moremo določiti. Razne oblike kuneolin se pojavljajo v plasteh barremija in aptija skupaj z Bačinella irregularis in Salpingoporella dinarica. Dobili smo jih v zbruskih 25 d, 28 b, 28 c, 28 d. Družina: LITUOLIDAE Haplophragmoides sp. 2. tab., 5. al. Hišica je planspiralna. Kamrice in stene so enostavne. Začetna kamrica je majhna, okrogla, okrog nje so v krogu nanizane mlajše kamrice, ki se postopno večajo in podaljšujejo. Spiralna linija se počasi odvija in postane pri mlajših kamricah bolj ravna. Mlajše kamrice so torej podolgovate in ozke. Vseh kamric je navadno 9 do 13 ali 14. Druga kamrica je zelo majhna, tretja in četrta pa sta navadno združeni v eno široko. Naši primerki so podobni vrsti H. scitulum, vendar so kamrice manj involutne. Tudi zavojna linija mlajših kamric je nekoliko bolj ravna kot pri vrsti H. scitulum. Velikost hišice je 0,4 mm do 0,65 mm. Dobili smo jih v plasteh barremija in aptija v zbruskih 23, 28 in 29. Primerki so zelo lepo ohranjeni. Opisali bi lahko novo- vrsto, vendar imamo za foraminifere premalo sodobne literature na voljo. Trochamminoides sp. 3. tab., 2. si. Hišica je okrogla s številnimi kamricami. Vse kamrice so približno enake velikosti in se zelo malo prekrivajo ali pa sploh ne. Zavojna linija je enakomerno okrogla. Zavoji so 3 do 4. Primerki rodu Trochamminoides nastopajo v skladih barremija in aptija skupaj s Haplophragmoides sp., Bačinella sp. in Salpingoporella dinarica. Zaradi pomanjkanja literature tudi pri teh primerkih nismo mogli določiti vrste. Družina: ORBITOLINIDAE Najnovejša študija in revizija orbitolinid je Douglassova razprava iz leta 1960. Med orbitolinide je prištel rodove Orbitolina, Dictyo-conus, Coskinolinoides, Simplorbitolina in Iraqia. Orbitolinide so značilne za dobo od barreimija do cenomana. Douglass pravi, da so se razvijale iz rodu Coskinolinoides prek rodu Simplorbitolina in da je za razvoj značilna delitev prekatov oziroma kamric. Za vrsto Orbitolina discoidea Gras je mnenja, dal je bolj primitivna obillika orbitolin, ker ima zunanje kamrice deljene samo na dva dela. Orbitolinide iz najdišč na Trnovskem gozdu so različnih oblik. Hišice imajo obliko ozkega ali širokega stožca, z deljenimi majhnimi ali velikimi zunanjimi kamricami. Nekatere oblike so bolj primitivne, druge bolj komplicirane. Zgradba se lepo vidi zlasti na zunanjih kamricah. Starejše so razcepljene navadno na dva dela, pri mlajših pa opazujemo že delitev na tri dele ali na dvakrat po dva dala. Opis vseh primerkov zahteva globljo samostojno študijo in jih bomo podrobneje obdelali mogoče kdaj v bodoče. V tem članku naj navedemo dve najbolj pogostni vrsti: Orbitolina co-noidea Gras in Orbitolina discoidea Gras. Orbitolina conoidea ima visoko stozčasto hišico. Največja višina hišice je 0,36 dO 1,32 mm, največja širina hišice pa 1,35 do 1,88 mm. Orbitolina discoide a pa ima naslednje dimenzije: največja višina hišice meri 0.79 do 1,12 mm, največja širina hišice pa 2,67 do 4,29 mm. Orbitoline smo dobili v skladih barremija in aptija v vzorcih 27, 30 in 32 (3. tab., 1. si.). Pregledno stratigrafsko razpredelnico orbitolinid sta podala B a s -soullet in Moullade (1962) iz barremijsko-aptijskih skladov Sierra du Montsech v Španiji. Rod Orbitolinopsis se po njunih ugotovitvah pojavlja v barremiju, Iraqia v spodnjem apfciju, Orbitolina pa v vsem aptiju. Vidimo torej, da so orbitolinide značilne za dobo od barremija do aptija ali še mlajše. V naših nahajališčih smo jih dobili skupaj z Bačinella irregularis in algo Salpingoporella dinarica, ki to starost potrjujeta. Crustacea Rod: Favreina Bronnimann 1955 Favre in Youkovsky sta neke fosilne oblike iz portlandija v Švici imenovala kot organizme »B«. Cuvillier je pozneje podobne oblike našel v spodnji kredi Akvitanije in jih prištel k haracejam. Parejas je te ostanke spoznal za izločbe nekaterih rakov. Dal jim je ime Coprolithus. Za holotip je določil Favrejevo obliko »B« in jo imenoval Coprolithus salevensis (po Bronnimannu, 1955). Bronnimann (1955) je opisal te iste oblike in jim po prvem najditelju dal ime Favreina. Za holotip je določil prav tako obliko »B« in jo imenoval Favreina youkovskyi. Enako vrsto je našel tudi na Kubi. Takrat še ni vedel, da je Pare j as opisal isto obliko pod drugim imenom. Bronnimann in Norton (1961) sta ponovno pregledala omenjene fosilne ostanke in ugotovila, da se Pa rž j as pri svojem opisu novega rodu ni držal vseh nomenklaturnih pravil. Med drugim mu ni določil položaja v sistemu. Zato naziv Coprolithus ni veljaven. Omenjena avtorja sta ga ukinila in uveljavila ime Favreina. Rod Favreina sta uvrstila v Crustacea. Ta naziv upoštevajo danes paleontologi. Edino holotip, ki ga je Bronnimann prvič imenoval Favreina youkovskyi, Parejas pa isto obliko že prej Coprolithus salevensis, se preimenuje v Favreina salevensis (Parejas). Favreina salevensis (Parejas) 2. tab., 4. si. 1955, Favreina youkovskyi, Bronnimann, pp. 40, Pl. 2, fig. 11, text f igj. 5 e—5 n. 1960, Coprolithus saleverwis, Radoičič, pp. 48, Tab. 7. 1961, Favreina salevensis, Bronnimann e Norton, pp. 835_838 fig. 1—3. To so organski ostanki nepravilne okroglaste ali podolgovate oblike. V podolžnem preseku vidimo v njih ozke paralelne kanale, brez kakršnekoli pravilne razporeditve. V prečnem preseku so ti kanali okrogli. Doslej je bila ta vrsta najdena v portlandiju v Švici, v zgornji juri Arabije, v spodnji kredi Francije in Kube ter v zgornji juri in spodnji kredi južnih Dinaridov. V Sloveniji je zelo pogostna. Na Trnovskem gozdu smo jo našli v skladih spodnje krede, v hauteriviju. Bogatejša najdišča so na Notranjskem in Dolenjskem. Nastopa v zgornjejurskih in spodnjekrednih skladih od zgornjega kimmeridgija do konca barremija. Favreina kurdistanensis Elliott 1962,F. kurdistanensis, Elliott, pp. 36, PI. 3. fig. 1—3, 6. Primerek je nepravilne oblike. Sosednji kanali so za razliko od vrste F. salevensis spojeni. V prečnem preseku ne dobimo posameznih okroglih cevčic, ampak sta po dve navadno spojeni, zato je videti, kot da so cevčice ali kanali v parih. Elliott je našel to vrsto v plasteh barremija v severnem Iraku. Pri nas na Trnovskem gozdu ni bila najdena, pač pa je zelo pogostna v Loškem potoku na Dolenjskem. Pojavlja se v skladih hauterivijske starosti. Incerte sedis Bačinella irregularis Radoičič 3. tab., 3. si. 1959, B. irregularis, Radoičič, pp. 89, Tab. 3. si. 1-2. 1960, B. irregularis, Radoičič, Tab. 17. sl.l. 1962, B. irregularis, Sartoni e Crescenti, pp. 271, Tav. 26. fig. 2, Tav. 29. Radoičičeva (1959) je B. irregularis opisala kot organizem, katerega celice so različne velikosti in nepravilne oblike. Razporejene so v skupine ali v neke vrste nepravilnih nizov, ki se med seboj prepletajo. Nov rod je uvrstila k algam z nejasnim sistematskim položajem. Njeno domnevo sta potrdila Sartoni in Crescenti (1962), ki sta enako obliko našla v spodnjekrednih skladih južnih Apeninov. Menita, da gre za posebne vrste apneno algo. Doslej ne poznamo nobene alge s podobno strukturo, niti pri algah ne moremo govoriti o kakršnih koli celicah, zato je uvrstitev rodu Bačinella med alge še nezanesljiva. Nekoliko se nagibamo k mnenju, da pripada posebni skupini hidrozojev, podobno kot Cladocoropsis. Različno oblikovane »celice« spominjajo na cenostilne cevi s tabulami. Tudi mikro-struktura skeletnih elementov je podobna hidrozojski. Ponekod zelo jasno vidimo temno osrednjo črto, okoli katere so radialno razvrščena vlakna. Podobne oblike kot je Bačinella smo dobili v vzorcih z Nanosa skupaj s hidrozofjem Cladocoropsis, zato je primerjava toliko bolj verjetna. Vrsta Bačinella irregularis je znana iz raznih krajev južne Dalmacije in Črne gore ter iz okolice Salerna v južni Italiji. Vedno se pojavlja v barremijskih skladih. Pri nas smo jo našli na Trnovskem gozdu pod skladi z algo Salpingoporella dinarica in ustreza barremijski stopnji spodnje krede. Dobili smo jo v vzorcih 23 in 27. Aeolisacus sp. Za majhne apnene cevčice, na obeh straneh odprte, je Elliott (1958) osnoval nov rod Aeolisacus z neznanim sistematskim položajem. Podolžna os je rahlo zakrivljena, stene so nepravilno okrogle. Ta avtor je opisal novo vrsto Aeolisacus dunningtoni iz permskih, zgornjetriadnih ter spodnje- in srednjejurskih skladov Bližnjega vzhoda. Radoičičeva je našla novo vrsto istega rodu v senonskih skladih Dugega otoka. Njena vrsta Aeolisacus kotori se razlikuje od vrste A. dunningtoni po večji debelini sten. Na Trnovskem gozdu so podobne oblike v aptijskih skladih skupaj z algo Salpingoporella dinarica. Naši primerki so povečini okrogli. Le redki so nekoliko ovalni. Mogoče so to samo prečni preseki daljših cevčic, ali pa le majhne kroglice, ki bi lahko predstavljale novo vrsto rodu Aeolisacus. Zaradi prekristaliziranosti in premajhnega števila primerkov nismo mogli določiti vrste. Stratigrafski del Italijanska raziskovalca Sartoni in Crescenti (1962) sta na podlagi mikropaleontoloških raziskav razčlenila sklade južnih Apeninov na več con ali horizontov. Imenovala sta jih po najznačilnejših fosilnih vrstah. Njuno razpredelnico za zgornjo juro in spodnjo kredo kaže 2. tabela. RAZDELITEV SKLADOV NA CONE PO SARTONIJU IN CRESCENTIJU THE DIVISION OF STRATA AFTER SARTONI AND CRESCENTI 2. tabela Table 2 aptij—valanginij cona s Cuneolina composaurii zg. titonij oona s Salpingoporella apenninica sp. titonij—kdmmeridgij cona s Clypeina jurassica in Vaginella striata lusitanij—callovij cona s Kur nubia palastiniensis Radoičičeva je stratigrafsko razdelilla južne Dinaride. Plasti ni imenovala po mikrofavni, pač pa je na podlagi mikrofavne določila vse stratigrafske člene zgornje jure in spodnje krede. Najznačilnejšo favno, ki jo je dobila v posameznih horizontih, kaže 3. tabela. STRATIGRAFSKA RAZDELITEV PLASTI PO RADOlClČEVI THE STRATIGRAPHIC DEVISION OF THE STRATA AFTER RADOlClC 3. tabela Table 3 aptij—barremij Salpingoporella dinarica — Bačinella irregularis hauterivij brez značilne mikrofavne valanginij velike tintinine infra valanginij Clypeina jurassica in velike tintinine portlandij—zg. kimmeridgij Clypeina jurassica sp. kimmeridgij—oxfordij Cladocoropsis mirabilis Do enakih ali podobnih rezultatov so prišli tudi drugi raziskovalci, vendar omenjamo samo ta dva razvoja, ker sta najpopolnejša, in ker je zanimiva primerjava z našimi nahajališči. Sartoni in Crescenti sta vso dobo od valanginija do aptija združila v eno samo cono s Cuneolina composaurii. Ta foraminifera je najznačilnejša. Poleg nje pa sta navedla še algo Salpingoporella dinarica, Bačinella irregularis in druge. Zapovrstnost mikrofavne v južnih Apeninih in v južnih Dinaridih je skoraj enaka. Razlika je le v nekaterih strati-grafskih razmejitvah, zlasti med portlandijem in valanginijem. Sartoni in Crescenti sta postavila mejo jura-kreda glede na mikro-favno mnogo više kot je postavljena v Dinaridih in drugod v Evropi in na Bližnjem vzhodu. Velike tintinine, ki sta jih italijanska avtorja imenovala Vaginella striata, sta uvrstila v spodnji titonij. Nista jih ločila od horizonta z algo Clypeina jurassica, v naših nahajališčih pa je ta razdelitev izrazita. Se celo cona s Salpingoporella apenninica, ki leži nad horizontom z velikimi tintininami, spada po njunem mnenju še v zgornji titonij. Kuneoline, orbitoline, Salpingoporella dinarica, Bačinella irregularis in druga mikrofavna, značilna za barremijsko-aptijske sklade, je v južnih Apeninih postavljena v dobo od valanginija do aptija, torej tudi že v najnižji del spodnje krede. Na ta način spodnja kreda v Apeninih sploh ni razčlenjena in je doba valanginija in hauterivija mikropaleontološko zelo pomanjkljivo raziskana. Na Trnovskem gozdu smo razčlenili sklade na podlagi mikrofavne podobno kot v južnih Dinaridih. Razlika je le v razmejitvi jure in krede. RAZDELITEV SKLADOV NA TRNOVSKEM GOZDU THE DIVISION OF STRATA IN TRNOVSKI GOZD 4. tabela Table 4 aiptij Salpingoporella dinarica barremlj Bačinella irregularis hauterivij favreine, Salpingoporella apenninica valanginij velike tintinine portlandij Clypeina jurassica in velike tintinine zg. kdmmeridgij Clypeina jurassica sp. kimmeridgij—oxfiordij hidrozoji, korale, hetetide Poleg značilnih fosilov, omenjenih v razpredelnici, najdemo v posameznih horizontih še drugo mikrofavno in mikrofloro: Zgornji malm: Clypeina jurassica, Salpingoporella annulata, redke solenopore, Cayeuxia sp., redke tekstularije, v zgornjem portlandiju se pojavijo še velike tintinine. Valanginij: velike tintinine Campbelliella mileši, Daturellina costata, Zetella sp. in drugi nedoločljivi odlomki tintinin, Salpingoporella annu-lata, S. apenninica, zelo pogostna je Cayeuxia sp. Dobimo še foraminifero Choffatella sp., miliolide, tekstularije in solenopore. Hauterivij: Favreina salevensis, redke miliolide, tekstularije in ver-neuilinide. Redki sta algi Salpingoporella annulata in S. apenninica. V hauterivijskem horizontu nismo dobili nobene značilne favne. Določeno oporo nam lahko nudijo vrste rodu Favreina. Pa peš (1963) je v Livnem ugotovil najštevilnejše favreine v hauteriviju. Tudi na Dolenjskem, zahodno od Loškega potoka, smo dobili najštevilnejše vrste rodu Favreina v skladih nad velikimi tintininami in smo jih uvrstili v hauterivij. Mogoče bomo z nadaljnjim raziskovanjem lahko pripisali nekaterim vrstam rodu Favreina večji stratigrafski pomen. Barremij: Bačinella irregularis, Haplophragmoides sp. Trochammi-noides sp., orbitolinide, Cuneolina sp., miliolide, tekstularije. Aptij: Salpingoporella dinarica, Cuneolina laurentii, Cuneolina sp., orbitolinide, miliolide. Stratigrafska razširjenost mikrofosilov je podana na 5. tabeli. Za točno zapovrstnost mikrofosilov po plasteh pa navajamo še mikropaleonto-loške analize vseh vzorcev iz profila pri Voglarjih (št. 17 do 32) od zgornjeportlandijskih do spodnjealbijskih skladov (6. tabela). Zaključki 1. Na ozemlju Trnovskega gozda je bila sedimentacija na prehodu iz zgornje jure v spodnjo kredo neprekinjena. V zg. malrnu nastopa značilna alga Clypeina jurassica. Mejo med juro in kredo postavljamo tam, kjer ta alga izumre. 2. Velike tintinine se pojavijo že v zgornjem portlandiju, najštevilnejše so v valanginiju in konec valanginija skupaj z nerinejami izginejo. Nerineje so zelo pogostne že v zgornjem malmu, nadaljujejo pa se še v spodnjo kredo. 3. Hauterivijske plasti vsebujejo redko mikrofavno. Najznačilnejše so favreine (F. salevensis), ki jih spremljajo redke alge iz rodu Salpingoporella. 4. Prvi pojavi orbitolinid in kuneolin ter vrsta Bačinella irregularis označujejo barremijsko stopnjo spodnje krede. 5. Starost aptijskih skladov je določena z algo Salpingoporella dinarica, ki je vodilna za ta horizont in je na Trnovskem gozdu zelo pogostna. Spremljajo jo orbitolinide, kuneoline ter redkejše druge forami-nifere. 6. V albijsko-cenomanijskih skladih se pojavljajo rekvienije, nerineje in orbitolinide. Albij in cenomanij se ne razlikujeta niti litološko niti po makrofavni. Mikrofavnistično tega horizonta nismo raziskali. STRATIGRAFSKA RAZSlRJENOST MIKROFOSILOV NA TRNOVSKEM GOZDU STRATI GRAPHICAL DISTRIBUTION OF MICROFOSILS IN TRNOVSKI GOZD 5. tabela Table 5 Zg. malm Valanginij Hauterivij Barremij Aptij Albij Upp. Malm Valanginian Hauterivian Barremiaii Aptaan Albiain Clypeina jurassica X X X X X X Salpingoporella annulata x 9. x x x X X X X X X X X X X X X Salpingoporella apenninica X X X X X X X X X X X Campbelliella mileši X X X X X X X X X X Daturellina costata X X X X X X X X X X Zetella sp. X X X X X X X X Vemeuilina sp. XXX X X X X X X X miliolide XX X X X X XX X X X X X X X X XX XXX tekstularije XX XXX XXX XXX X XXX X X X Trochamrninoidea sp. X X X X X X X X X X X X Haplophragmoides sp. X X X X X X X X X Bačinella irregularis X X X X X X Cuneolina sp. X X X X X X X X X Cuneolina laurentii X X X X Orbitolinidae X X X X X X X X X X X XXX Salpingoporella dinarica X X X X X X Aeolisacus sp. X X Favreina salevensis X X X X X MIKROPALEONTOLOŠKE ANALIZE IZ PROFILA PRI VOGLARJIH MICROPALAEONTOLOGICAL ANALYSES OF SAMPLES FROM SECTION AT VOGLARJI 6. tabela Table 6 Stratigr. horizont stratigr. Horizon Številka vzorca Number of samples Mikrofavna Microfauna Albij? Albian? Aptij Aptian 32 31 30 29 28 Orbitolina conoidea, O. discoidea, Miliolidae Salpingoporella dinarica, Miliolidae Salpingoporella dinarica, Orbitolinidae, Miliolidae, Tex tul ari dae Haplophragmoides sp., Verneuilina sp., Miliolidae Cuneolina laurentii, Salpingoporella dinarica, Haplophragmoides sp., Trochamminoides sp., Verneuilinidae, Aeolisacus sp. Barremdj Barremian 27 26 25 24 23 Bačinella irregularis, Orbitolinidae Miliolidae, Textularidae Cuneolina laurentii, Miliolidae brez mikrofavne — without microfauna Bačinella irregularis, Haplophragmoides sp., Trochamminoides sp., Orbitolinidae, Verneuilinidae, Miliolidae, Textularidae Hauterivij Hauterivian 22 21 Salpingoporella annulata, S. apenninica, Fa-vreina sp., Miliolidae Verneuilina sp., Textularidae, Miliolidae Valanginij Valanginian 20 19 18 Cayeuxia sp., Salpingoporella apenninica, S. annulata, Daturellina costata brez mikrofavne — without microfauna Campbelliella mileši,. Daturellina sp., Zetella sp., Salpingoporella annulata Zg. portlandij Up. Portlandian 17 Clypeina jurassica, Tintinnina, Cayeuxia sp. Sp. portlandij Zg. kimmeridgij L. Portlandian U. Kimmeridgian Clypeina jurassica Sp. kimmeridgij —oxfordij L. Kimmeridgian —Oxfordian Hydrozoa, Anthozoa, Chaetetidae THE DEVELOPMENT OF THE LOWER CRETACEOUS BEDS AND THE BOUNDARY BETWEEN JURASSIC AND CRETACEOUS FORMATIONS IN THE WESTERN PART OF TRNOVSKI GOZD The micropalaeontological analyses of samples from several localities of Trnovski gozd (Southwestern Slovenia), have enabled us to distinguish some stratigraphical horizons of the Lower Cretaceous. There have been established: Valanginian, Hauterivian, Barremian, Aptian and Lower Albian. The stratigraphic sequence of Trnovski gozd can be compared with the same horizons in Dalmatia and in Southern Italy. Similar relations occur also in some places of Lowland and Inland Slovenia. The former investigators distinguished in the Upper Jurassic of Trnovski gozd the sphaeractinian and the coral limestones, and in the uppermost part the nerinean limestone, which was ranged as a whole into the Tithonian stage. The coral and sphaeractinian limestones up to now have been compared with the Stramberk horizon. On the basis of the micropalaentological evidence the authors succeeded to demonstrate that the greater part of the nerinean limestone, till now placed in the Upper Jurassic, belongs to the Lower Cretaceous, namely to Valanginian and Hauterivian. The Upper Malmian strata are developed especially well at Krnica east of Trnovo, and near the village Rijavci. These strata occur as white to brownish grey compact and well stratified limestone alternating with brown oolitic limestone. From the Upper Malmian to Albian strata the following microfossils have been determined: Algae: Clypeina jurassica Favre Salpingoporella annulata Carozzi Salpingoporella apenninica Sartoni e Crescent! Salpingoporella dinarica Radoičič Foraminifera: Verneuilina sp. Cuneolina laurenti Sartoni e Crescent! Cuneolina sp. Haplophragmoides sp. Trochamminoides sp. Chojjatella sp. Orbitolinidae Miliolidae Textularidae Tintinninae: Campbelhella mileši Radoičič Campbelliella sp. Daturellina costata Radoičič Daturellina sp. Zetella sp. Crustacea: Favreina salevensis (Parejas) Favreina kurdistanensis Elliott Favreina sp. Incertae sedis: Bačinella irregularis Radoičič Aeolisacus sp. Clypeina jurassica Favre is well exposed in the area of Trnovski gozd, but the beds of this leading alga are in some localities thinner in comparison with finding places of Notranjska and Dolenjska. S alping o p or ell a apenninica Sartoni e Crescenti. This alga is similar to S. annulata, but it is smaller and has among particular verticils the furrows which are easily seen. S. apenninica was found by Sartoni and Crescenti (1960) in the "Cone with S. apenninica", and allocated to the Upper Tithonian in South Appennins. It lies above the horizon with Large Tintinninae, which are characteristic for Valan-ginian, therefore we suppose that "cone with S. apenninica" is younger than Valanginian, and anyhow younger than the Upper Portlandian. In our country alga S. apenninica has been found together with Large Tintinninae in Valanginian and together with favreins in Hauterivian beds. S alping o p or e 11 a dinar ica Radoičič has been described for the first time in Slovenia. It is abundant in the Aptian horizon and is one of the leading fossil of this period. Our specimens correspond with the description of Radoičič, but some of them are smaller than up to this time known forms. The measurements of alga S. dinarica from Trnovski gozd are as follow: after Radoičič: diameter of alga 0,13—0,49 mm (0,24—0,56 mm) diameter of axial tube 0,07—0,26 mm (0,128—0,400 mm) At the first time Radoičič allocated Salpingoporella dinarica and Bačinella irregularis to one horizon of the Barremian-Aptian age. They were also ranged in the same period by Italian investigators Sartoni and Crescenti, and by Elliott, who described S. dinarica as Hensonella cylindrica from Iraq (Sartoni e Crescenti, 1962). Now-a-days predominates the opinion that S. dinarica belongs to the upper part of the Barremian-Aptian strata; consequently S. dinarica is characterisecal for the Aptian horizon. ? Large Tintinninae. The fossil forms which were denoted by Favre as organism "C", and later C a r o z z i determined them for pteropods and named them Vaginella striata (Carozza, 1954), Radoičič allocated to- Ciliata to the group of Tintiimina, and erected new independent genera with many species. (Radoičič, 1959, 1963). Farinacci has all the above mentioned fossils combined into one species Banfcia striata (Carozzi), and allocated them to the Lamellibran-chiata of the family Teredinidae. The same author says that the reduplication, which appears at this organism, is so far not known at Ciliata. Besides she points out that the wall of well preserved examples consists of a thin internal layer and an external one (Farinacci, 1963). We have examined a lot of material and discovered the "double walls" only at reduplicated specimens. The reduplication is, however, particularity so for the mussels as for the tintinnins. We appreciate the opinion and the statements of R a d o i č i č, and place the problematic fossils among the Tintinninae, until their systematical position is not finally solved. On the territory of Trnovski gozd the Large Tintinninae are not so good preserved as in some localities of Lowland Slovenia. All the species, we have established (Campbelliella rnilesi, Daturellina costata, Zetella sp.) were already described in our country (Turnšek, 1964). According to that we mention them only as a new finding place in Trnovski gozd. The Large Tintinninae appear already in the Upper Portlandian together with Clypeina jurassica, but there are more numerous in Va-langinian beds, where they appear like stonebuilders. Foraminifera. The various forms of miliolids, textularids, and verneuilinids occur in all the layers from the Upper Jurassic to Albian. Their existence is not of considerable importance for the stratigraphy of the Lower Cretaceaous beds. There have been found Cuneolina laurentii Sartoni e Crescenti, Haplophragmoides sp., Trochamminoides sp. and Orbitolinidae. Favreinae. The rests of favreins are rarely found in Trnovski gozd. Only one species F. salevevisis (Parejas) has been determined. It occurs in the beds of the Hauterivian age. B a č in e 11 a irregularis Radoičič. R a d o i č i č (1959) has the new genus Bačinella described as fossil organism, which is consisted of cells of different size and irregular forms. These are arranged into the groups or series, which are irregularly interlaced. Genus has been allocated to Algae, its systematic position has not been obvious. Sartoni and Crescenti have found Bačinella in the beds of Lower Cretaceous in South Appennins, and they suppose to deal with a special form of calcareous Algae. So far we do not know any alga with similar structure. The tubes at solenopors are parallel. We consider, that Bačinella belongs to the special group of hydrozoans, like Cladocoropsis. Different forms of "cells" with partings in Bačinella remind us of coenosteal tubes and interspaces with tabulae in hydrozoans. Also the microstructure of skeletal elements in Bačinella resembles to that of hydrozoans. In some elements of Bačinella we can obviously notice the medial dark line with radial fibrous. In the area of Trnovski gozd Bačinella has been found under the strata with Salpingoporella dinarica, and corresponds to the Barremian stage of the Lower Cretaceous. 35 — Geologija št. 9 545 Conclusions The micropalaeontological analyses of samples from Trnovski gozd show the following results: 1. Sedimentation from the Upper Jurassic to Lower Cretaceous evolved uninterruptedly. The boundary between the Portlandian and the Valanginian is erected there, where Clypeina jurassica became extinct. 2. The Large Tintinninae appear already in the Upper Portlandian, more frequent they are in the Valanginian. At the end of Valanginian the Large Tintinninae together with Nerineae became extinct. 3. The Hauterivian strata seldom contain microfauna. The most common are favreins (Favreina salevensis), accompanied by rare Salpingoporella annulata and S. apenninica. 4. Bačinella irregularis and the first appearance of cuneolins and orbitolinids characterize the Barremian stage of the Lower Cretaceous. 5. The age of Aptian beds is determined by the alga Salpingoporella dinarica which is often found on Trnovski gozd. 6. The strata with Salpingoporella dinarica are overlain by the Albian-Cenomanian beds, containing the fragments of Requieniae, and Radiolites together with Orbitolinidae. A precise succession of microfauna in Upper Malmian and Lower Cretaceous and the division on the individual stratigraphic horizons is given in the Slovenian texte on the tables 5 and 6. LITERATURA Bassoullet, J. P. & Moullade, M., 1962, Les Orbitolinidae du ?retac6 limferieur de la Sierra du Montsech, Province de Lerida (Espagne). Rev. Micropaleont., 5, 2; 104—114, Paris. Bronnimann, P., 1955, Microfossils incertae sedis from the Upper Jurassic and Lower Cretaceous of Cuba. Micropaleontology, 1, 1; 28—51, New York. 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Canovic, M., 1959, Neki mikropaleontološki podaci za izdvajanje sedime-nata don je krede na terenu Trebinje (Hercegovina). Geol. glasnik, 3. 23—27, Tab, 1-2, Titograd. Canovič, M., 1959, Prilog m ikropaleon tološ kom proučavanju sedi mena ta gornje jure na graničnom terenu Črne gore, Hercegovine i dubrovačkog Primiorja. Geol. glasnik, 3, 71—78, Tab. 10—13, Titograd. Douglass, H. C., 1960, Revision of the family Orbitolinidae. Micropaleonto-logy, 6, 3; 249—264, PL 1, New York. Elliott, G. F., 1962, More microproblematica from the Middle East. Micro-paleontology, 8, 1; 29—44, Pl. 1—6, New York. Farinacci, A., 1963, L'«Organismo C» Favre 1927 appartiene alle Teredi-nidae. Geologica Romana, 2, 151—178, Tav. 1—5, Roma. G or j anovi č-Kramber ger, C., 1895, Fosilne ribe Komena, Mrzleka, Hvara i M. Libanona Jugosl. akad. znanosti i umjetnosti. Zagreb. H a u e r, F., 1868, Geologische tTbersichtskarte der osterreichischen Monarchie, Blatt VI, Oestliche Alpenlander. Jahrb. k. k. geol. R. 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P a p e š, J., 1963, O razvoju i mogučnosti rasčlanjivanja donje krede u području Livna. Geol. glasnik, 7, 33—38, Sarajevo. Pleničar, M., 1960, Stratigrafski razvoj krednih plasti na južnem Primorskem in Notranjskem. Geologija, 6, 22—145, Ljubljana. Pleničar, M., 1963, Tolmač k osnovni geološki karti FLRJ, list Postojna. Manuskript, Geološki zavod, Ljubljana. Pokorny, V., 1958, Grundzuge der zoologischen Micropalaontologie. Lituo-lidae, pp. 186—189, Berlin. Radoičič, R., 1959, Salpingoporella dinarica nov. spec, u donjokrednim sedimentima Dinarida. Geol. glasnik, 3, 33—42, Tab. 3—5, Titograd. Radoičič, R., 1959, Paleontološke odlike sediimenata okoline Bačinskog jezera (Gradac—Ploče). Geol. glasnik, 3, 55—63, Tab. 7—9, Titograd. Radoičič, R., 1959, Krupne tintinine CampbellielLa nov. gen. i Da ture! lina nov. gen. Vestnik Zavoda za geol. i geofiz. istraž. Srbije, 17, 79—86, Tab. 1—2, Beograd. Radoičič, R., 1959, Nekoliko problematičkih mikrofosila iz dinarske krede. Vesnik Zavoda za geol. i geofiz. istraž. Srbije, 17, 87—92, Tab. 1—2, Beograd. Radoičič, R., 1960, Mikrofacije krede i starijeg tercijara spoljnih Dinarida Jugoslavije. Paleontologija Jugosl. Dinarida. Ser. A, Mikropaleontologija, 4, 1; Titograd. Radoičič, R., 1962, Paleoekologija i biostratigrafija aberantnih tintinina Jugoslavije. Doktorska disertacija, manuskript, Beograd in Ljubljana. Sartoni, S. & Crescenti U., 1962, Ricerche biostratigrafiche nel Me-sozoico dell'Appennino meridionale. Giornale dd Geologia. Ann. M us. Geol. Bologna, Ser. 2, Vol. 29 (1960—1961), 161—304, Tav. 11—42, Bologna. S tac he, G., 1889, Die Liburnische Stufe und deren Grenz-Horizonte. Abh. geol. R. A., Wien. S tur, D., 1858, Das Isonzo-Thal von Flitsch abwarts bis Gorz, die Umgebun-gen von Wippach, Adelsberg, Planina und Wochein. Jahrb. k. k. geol. R. A., Wien. Turnšek, D., 1965, Velike tintinine iz titonskih in valangijskih skladov severozahodne Dolenjske. Geologija 8, 102 do 112, Ljubljana. Vet ter s, H., 1947, Erlauterungen zur geologischen Karte der Republik Osterreich und seinen Nachbargebdeten. Wien. Winkler, A., 1924, Ueber den Bau der ostlichen Siidalpen. Mitt. Geol. Ges., Wien. Wiontzek, H., 1934, Rudisten aus der oberen Kreide des mittleren Isonzo-gebietes. Pal aeon tographica, Stuttgart. HIPERSTENOV ANDEZIT PRI SV. ROKU OB SOTLI Ernest Faninger Z 1 sliko med tekstom V terciarju je bilo na Slovenskem močno vulkansko delovanje. Večina izbruhov je bila v spodnjem miocenu, vendar pa se je vulkanizem ponekod pojavil že v oligocenu (H a m r 1 a , 1955). Terciarni vulkanizem se je končal v pliocenu z izlivi bazaltne lave; sledove te zadnje faze najdemo le v skrajnem severovzhodnem delu Slovenije. Za oligocensko-miocenski vulkanizem na slovenskem ozemlju so značilni predvsem andeziti in daciti ter njihovi grohi. Andeziti so povečini avgitni, redkeje hiperstenovi, daciti pa rogovačni ali biotitni, oziroma hloritni, kadar hlorit nadomešča biotit. Avgitni andezit je razširjen predvsem okoli Šaleške doline; najdemo ga na Smrekovcu, pri Belih vodah in drugod. Kot nahajališče hiperstenovega andezita navaja Teller (1898) Št. Ilj pri Dramljah. Daciti so v zahodnem delu Pohorja ter v bližnji dolini reke Drave in v šaleški dolini. Andezite na Slovenskem omenjajo številni avtorji v geoloških (Teller, 1898) in petrografskih razpravah (Graber, 1929), njihovega popolnega petrografskega opisa pa doslej še ni nihče objavil. V našem članku bomo obdelali le predornino od Sv. Roka ob Sotli, ki jo je Hatle (1881) označil kot avgitni andezit in kasneje še D r e g e r (1920) kot roženast trahit. Temno siva do črna predornina pri Sv. Roku ob Sotli je spodnje miocenske starosti in kaže porfirsko strukturo. Njene glavne sestavine so vtrošniki plagioklazov (12 vol. °/o) in rombičnih piroksenov (5 vol. %), ostalo, razen drobnih zrnc magnetita, pripada temni amorfni osnovi, ki pe ima tudi tanjše svetlejše pasove. Plagioklazovi vtrošniki ustrezajo po optičnih lastnostih visokotempe-raturnim modifikacijam. Njihova sestava niha med 60 °/o in 71 °/o an — srednja vrednost sedmih meritev ustreza labradoritu s 65 °/o anortitne komponente (Zavarickij , 1958). Pri rombičnih piroksenih pa opazimo nihanje kota optičnih osi med —53° in —63°; kot srednjo vrednost pri štirih meritvah dobimo 2 V = —59°, kar ustreza hiperstenu s 37 °/o fero-silitne komponente (Troger, 1956). Kamenino pri Sv. Roku ob Sotli moramo torej po njeni modalni sestavi, strukturi in starosti imenovati andezit, točneje hiperstenov labra-doritov andezit. Oglejmo si še kemično sestavo kamenine in klasifikacijo na kemični podlagi; analizo in ustrezne magmatske parametre vidimo v 1. tabeli. Za predornino pri Sv. Roku ob Sotli je predvsem značilna visoka količina proste kremenice v normativni sestavi; zato se tudi Nigglijevi parametri ujemajo z normalno kremenovo dioritsko magmo in ne z dioritsko, kot bi pričakovali glede na njeno modalno sestavo, ki nima kremena v vtroš-nikih. Toda visoka količina proste kremenice v normativni sestavi nam da slutiti, da je tudi kremen bistvena sestavina amorfne osnove. Rombični pirokseni v modalni sestavi so v popolnem soglasju z normativno sestavo, saj je pri njej wolastonitna komponenta tako majhna, da je ni treba upoštevati in tako pripadajo tudi v normativni sestavi praktično vsi pirokseni rombični vrsti. Naša kamenina ustreza torej po Nigglijevih parametrih normalnemu kremenovemu dioritskemu tipu magme in ne dioritskemu (B u r r i, 0 M SI. 1. — Abb. 1 Primerjava magmatske kamenine od Sv. Roka ob Sotli z andezitom in dacitom Vergleich des Eruptivgesteines von V. Rok ob Sotli mit Andesit und Dacit Označba Kamenina Bezeichnung Gestedn 1 Andezat od Sv. Roka ob Sotli 2 Andezit (Troger, 1935) 3 Dacit (Troger, 1935) Q L M 49.2 39,7 11,1 35,8 43,3 20,9 52,0 35,5 12,5 1959), kot bi pri andezitih v splošnem pričakovali. Zato nastane vprašanje, ali smo s kemičnega vidika sploh upravičeni, da imenujemo našo kamenino andezit. Tudi primerjava vrednosti QLM (Burri, 1959) s tipičnim andezitom in dacitom, ki ju navaja Troger (1935), nam pokaže, da zavzema sicer naš vzorec neko vmesno lego med obema kameninama, vendar je njegova projekcijska točka mnogo bliže dacitu kot andezitu (1. slika). Tudi primerjava istih kamenin s pomočjo parametrov Zavarickega nam pove, da se po kemičnih lastnostih naša kamenina mnogo bolj približuje dacitu kot andezitu, saj je vrednost d proti dacitu 3,1, proti andezitu pa 9,5 (Sawarizki, 1954). Po kemičnih lastnostih gre torej prej za dacit kot za andezit. Toda za klasifikacijo magmatskih kamenin je merodajnejša modalna sestava, ki kaže, da je naš vzorec tipični andezit. Kemična sestava pa nam je le važno dopolnilo, ki kaže, da je predornina od Sv. Roka bolj kisla, kot bi pri andezitih pričakovali. HYPERSTHENANDESIT BEI SV. ROK OB SOTLI Im Terziar hat es in Slowenien eine starke vulkanische Tatigkeit gegeben. Der groBte Teil der Ergiisse fand im unteren Miozan stat, doch es gibt auch Anzeichen dafur, dafi einzelne Ausbruche schon im Oligozan statgefunden haben (H a m r 1 a , 1955). Die terziare vulkanische Tatigkeit fand im Pliozan mit Basaltergussen ihren AbschluB, doch ist diese letzte Phase nur an das auBerste nordostliche Gebiet Sloweniens beschrankt. Die Spuren des oligozan-miozanen Vulkanismus sind in Slowenien sehr haufig. Es handelt sich vorwiegend um Andesite und Dacite, die haufig von Tuffen begleitet werden. Bei den Andesiten unterscheidet man Augit- und Hypersthenandesite, bei den Daciten treten aber als femische Einsprenglinge gewohnlich Hornblende und Biotit bzw. Chlorit auf. Die Aufgabe unserer Abhandlung ist die petrographische Beschrei-bung des aus unterem Miozan stammenden ErguBgesteines, das bei Sv. Rok ob Sotli — einer Ortschaft ostlich von Rogatec — auftrit. Das Gestein wurde erstmals von H a 11 e (1881) als Augit-Andesit beschrieben und spater von D r e g e r (1920) als Hornfelstrachyt bezeichnet. Das dunkle ErguBgestein von Sv. Rok ob Sotli weist eine porphyrische Struktur auf. Als Einsprenglinge treten Plagioklase (12 Vol. °/o) und rhombische Pyroxene (5 Vol. °/o) auf, den Rest, auBer uberall im Gestein auftretenden winzigen " Magnetitkornchen, bildet eine dunkle Grund-masse, die auch schmalere lichtere Bander aufweist. Die Plagioklaseinsprenglinge entsprechen der optischen Eigenschaften nach den Hochtemperaturformen (Zavarickij, 1958). Ihre Zusam-mensetzung schwankt zwischen 60 % und 71 %> An — der Mittelwert von sieben Messungen weist einen Gehalt von 65°/oAn auf und entspricht sonach einem Labradorit. Bei den rhombischen Pyroxenen aber schwankt der Winkel der optischen Achsen zwischen —53° und —63° — und der Mittelwert von vier Messungen ergab 2V = —59°; auf Grund dessen entscprechen die rhombischen Pyroxenen einem Hypersthen mit 37% Ferosilitkomponente. Der mineralogischen Zusammensetzung, Struktur und Alters nach muB das Gestein von Sv. Rok ob Sotli als Andesit, ge-nauer gesagt als Hypersthenlabradoritandesit, klassifiziert werden. Die chemische Zusammensetzung ist in der Tabelle 1 ersichtlich. Es ist zunachst darin eine fur die Andesite ungewohnlich grofie frei Quarz-menge auffallend. Auch die Niggli-Werte entsprechen nicht einem dioriti-schen sondern einem normalen quarzdioritischen Magma (B u r r i, 1959), obwohl man bei den Andesiten in allgemeinen ein dioritisches Magma erwarten solite. Auch der Vergleich der QLM-Werte mit einem typischen Andesit und Dacit, die von Troger (1935) angegeben werden, zeigt uns, daB das Gestein von Sv. Rok ob Sotli zwar eine Zwischenstellung zwischen beiden Gesteinstypen einnimmt, doch es kommt an der Zeich-nung (Abb. 1) viel naher an den Dacit als an den Andesit zu liegen. Auch der Vergleich des Chemismus derselben Gesteinen mittels der Zavarickij-Parameter (Sawarizki, 1954) zeigt uns eine viel groBere Annahe-rung an den Dacit als an den Andesit, denn d gegeniiber Dacit hat den Wert 3,1, gegenuber Andesit aber 9,5. Nach der chemischen Zusammensetzung miiftte das Gestein von Sv. Rok ob Sotli eher Dacit als Andesit angesprochen werden. Doch weil fur die Klassification der Eruptiv-gesteinen die modale Zusammensetzung maBgebender ist, und nach dieser wird unser Gestein als Andesit betrachtet, muB dieser Name beibehalten werden. Doch die chemische Zusammensetzung gibt uns Auskunft, daB das Gestein von Sv. Rok ob Sotli saurer ist als nach der mikroskopischen Untersuchung zu erwarten ware. Da als Eindsprengling kein Quarz vor-handen ist, muB der normative QuarziiberschuB in der amorphen Grund-masse enthalten sein. Durch die niedere Wollastonitmenge in der normativen Zusammensetzung ist das Auftreten der rhombischen Pyroxenen in der modalen Zusammensetzung vollkommen erklarlich. LITERATURA B u r r i, C., 1959, Petrochemische Berechnungsmethoden auf aquivalenter Grundlage, Basel. Dreger, J., J920, Erlauterung zur geologischen Karte SW-Gruppe Nr. 94. Rohitsch und Drachenburg, Wien. Graber, H. V., 1929, Neue Beitrage zur Petrographie und Tektomik des Kristallins von Eisenkappel in Sudkarnten, Mitt. d. Geol. Ges in Wien XXII. Band. Ham r la, M., 1955, Poročilo o geologiji zahodnega dela in obrobja Šaleške doline, Arhiv geološkega zavoda v Ljubljani. Hattle, E., 1881, Zur Kenntniss der petrographischen Beschaffenheit der sudsteirischen Eruptivgesteine. Mitt, naturw. Vereins fiir Steiermark Jg. 1880, 17, 22 do 500, Graz. Sawarizki, A. N., 1954, Einfuhrung in die Petrochemie der Eruptivgesteine, Berlin. Strmole, D., 1960, Odnosi med magmatskimi kameninami okolice Belih vod, Velenja in Dobrne, njihova starost in geneza (naloga za strokovni izpit, Univerza v Ljubljani). Teller, F., 1898, Erlauterung zur geologischen Karte SW — Grupoe Nr 84 Prassberg, Wien, 1898. Tovšak, R., 1959, Andeziti in tufi iz Smrekovca (naloga za strokovni izpit Geološki zavod v Ljubljani). Troger, W. E., 1935, Spezielle Petrographie der Eruptivgesteine, Berlin. T r o g e r, W. E., 1956 Optische Bestimmung der gesterinsbildenden Minerale, Teil 1, Stuttgart. Zavarickij A. N., Sobolev V. S., Kvaša L. G., Kostjuk V. P. i Bobrievič A. P., 1958, Novye diagrammy dlja opredelenija sostava vysokotemperaturnyh plagioklazov. — Zapiski min. obšč. 87, vyp. 5, 529—541. 1. tabela Tabelle 1. HIPERSTENOV ANDEZIT PRI SV. ROKU OB SOTLI HYPERSTHENANDESIT VON SV. ROK OB SOTLI a) Kemična analiza in sistem CIPW Analitik: Max Wei bel, Zurich Utež. % s1o2 = 63,6 Q — 21,90 TiO* = 0,51 or = 6,40 AhOt 15,5 ab = 33.82 Fe203 — 1,4 an = 21,14 FeO = 3,8 j wo = 0,03 MnO = 0,10 di- J en = 0,02 MgO = 1,9 |ls = 0,01 CaO = 4,5 hy < ( en — 4,70 NasO = 4,0 Us = 5,13 k2o = 1»! mt — 2,08 paos — 0,16 il — 0,91 h2o+ — 3,0 ap = 0.36 h2o- 0,6 Sal _ 83,26 100,17 Fem — 13.24 h2o rr 3,6 Sistem CIPW Sal 83,26 Fem 13,24 Q 21,90 F 61,36 NažO' + KjO' _ 760 CaO' 760 KaO' 115 Na2Oy 543 6.3 0.36 1,00 0.18 CIPW (I) II. 4. 3. 4 (5). 100,10 b) Nigglijevi magmatski parametri in ekvivalentna norma (Burri, 1959) Nigglijevi parametri si — 248,0 ti = 1,41 P = 0,23 al = 35,6 fm = 27,9 c — 18,7 alk = 17,8 k — 0,15 mg = 0,40 qz =+76,8 Magma: normalna kremenovo dioritska baza dopolnilni parametri katanorma Q = 49,19 71 = 0,35 Q = 20,83 Kp = 4,00 r = 0,01 Or = 6,67 Ne = 22,47 /* = 0,45 Ab = 37,45 Cal = 13,24 k' = 0,15 An = 22,07 Cs = 0,05 mg' = 0,45 Wo = 0,06 Fs = 1,57 En = 5,45 Fo = 4,09 Hy = 5,21 Fa = 4,70 Q = 49,19 Mt = 1,57 Ru = 0,35 L = 4,70 Ru - 0,35 Cp = 0,34 M - 11,10 Cp = 0,34 100,00 100,00 Sestava plagioklazov: 37,1 % An c) parametri Zavarickega a = 10,8 r = 58,5 n = 84,9 c = 5,4 m' = 38,2 t = 0,6 b = 8,7 c' = 3,3 •P = 14,6 s = 75,1 Q =-1-23,2 POROČILO O DELU SLOVENSKEGA GEOLOŠKEGA DRUŠTVA V LETIH 1963 DO 1965 Mario Pleničar V tem času je društvo iskalo stikov s slovenskimi in drugimi jugoslovanskimi ter inozemskimi geologi. Tesneje se je povezalo tudi s predavatelji geologije na srednjih šolah. Jeseni 1963 je organiziralo skupno z zavodom za napredek šolstva tečaj geologije za srednješolske predavatelje. Geološko društvo je preskrbelo predavatelje, ki so tečaj vodili. Na tečaju so obravnavali predvsem teoretična vprašanja. Podobni prihodnji tečaji naj bi zajeli praktično uporabo geoloških izsledkov in metod v gospodarstvu. Malo pred tem Časom je bil tudi dokončno izdelan diafilm kot učni pripomoček za pouk geologije. Društvo je povabilo v Ljubljano več tujih geologov, ki so imeli pri nas predavanja in so se udeležili z nekaterimi člani društva geoloških obhodov. V tem času je bil dvakrat v Ljubljani dunajski paleontolog dr. Othmar Kiihn, častni član Slovenskega geološkega društva in dopisni član SAZU, dalje sta nas obiskala znani poljski sedimentolog dr. Stanislav Djulinski in sovjetski tektonik dr. Adran Sorski j. Jeseni 1964 je društvo sodelovalo pri organizaciji geološke ekskurzije avstrijskega in nemškega geološkega društva po Sloveniji ob priliki geološkega posvetovanja na Dunaju. Društvo je za to ekskurzijo izdalo poseben vodič. Ekskurzijo so vodili trije naši člani (dr. Dušan Kuščer, dr. Anton Ramovš in Ančka Ravnik-Hinterlechner). Prek Zveze geoloških društev je naše društvo poslalo dva člana na geološko posvetovanje o terciarju v Pečuh na Madžarskem. Kot gosta Madžarskega geološkega društva so ju peljali še v Budimpešto, ter jima omogočili stike z raznimi geološkimi strokovnjaki. Razen v poletnih mesecih je društvo organiziralo vsakih 14 dni strokovno predavanje ali diskusijski večer. Od 25. 1. 1963 do 20. 3. 1965 so bila naslednja javna predavanja: 25.1.1963 S. Gadžič, Hidrogeologija izvirnega območja Pive 1.2. F. Habe, Geološko-morfološki paberki s poti po norveških le- denikih in fjordih 22. 2. T. S. Lowering, The search for blind ore-bodies in the East Tintic district, Utah 15. 3. D. Kuščer, Geološki vtisi s potovanja v Romunijo 8. 3. M. Dolenc, Stanje železovih, svinčevih in cinkovih rudnikov v Alžiriji 5. 4. R. Gospodarič, Geološki izlet v Poljske Tatre in predgorje 25.4. H. Usova, Prikaz serije diapozitivov za pouk geologije na srednjih šolah 16. 5. skupno z Geografskim društvom: M. Šifrer, O historičnih gi- banjih ledenikov v Otztalskih in naših Alpah 12.6. skupno z Geografskim društvom: N. Cadeževa, Povojna bar- vanja ponikalnic v Sloveniji 25.10. O. Kiihn, Geološko potovanje v Etiopijo 8.1.1964 Diskusijski večer o hidrogeološkem standardu; vodil ga je dr. Dušan Kuščer 22.1. Napovedano predavanje S. Božičeviča o krasu v Liki je od- padlo, ker se referent ni javil. Namesto predavanja smo predvajali diapozitive o podmorskem svetu. Tolmačil je D. Kuščer 19. 2. M. Pleničar, O geoloških raziskovanjih v Alžiriji 11.3. S. Buser, Geologija Trnovskega gozda 25. 3. S. Buser, Geologija Vipavske doline 8. 4. M. Iskra, Geologija Savskih jam 22. 4. V. Bohinc, Vtisi s poti po Grčiji 28. 10. J. Perkavac, Metode sledenja kraških vod 18.11. F. Habe, Etna in Vezuv 9.12. S. Janežič, Odvodnjavanje zgornjerenskega premogovnega bazena 23. 12. R. Pavlovec, Geološki vtisi s Kephallenie in Ithake 13. 1. 1965 D. Ravnik, O geoloških raziskovanjih v Etiopiji in Eritreji 27. 1. Diskusija o standardu inženirsko-geološke karte. Vodil jo je F. Drobne 17. 2. M. Breznik, Hidrogeološke razmere pokrajine Jezire v Siriji 3. 2. J. Duhovnik, Ogled rudišč in organizacija raziskovalnega dela v Bolgariji 20. 3. 1965 Za občni zbor smo pripravili naslednje kratke referate: M. Dolenc, Geološke raziskave v tujini in perspektive E. Faninger, Magmatske kamenine v severni Sloveniji F. Drobne, Geologija Ljubljane T. Nosan, Hidrogeološke in inženirsko-geološke raziskave v Sloveniji Dolgoletni društveni referent za šolstvo prof. Usova je napisala v tem času že drugi učbenik za pouk geologije na srednjih šolah. Prednost tega učbenika je predvsem v tem, da navaja primere za razne geološke značilnosti in pojave na slovenskem ozemlju in v mejah Jugoslavije. Drugi člani so priobčevali svoje izsledke v domačih in tujih strokovnih revijah. RIHARDU ŠIMNOVCU V SPOMIN Šestega maja 1966 zvečer je ugasnilo življenje Riharda S i m n o v c a , moža, ki je 45 let svojega življenja posvetil slovenskim geologom in slovenski geologiji. Rodil se je 3. aprila 1891 v ljubljanskem Trnovem. Po končani štirirazredni ljudski šoli na Grabnu in petih letnikih umetnoobrtne strokovne šole je delal kot pohištveni mizar in strokovni risar pri raznih podjetjih doma in v inozemstvu. Kot je bila takrat navada, je po končanem uku odšel z doma, da bi se izpopolnil v stroki in si nabral življenjskih izkušenj. Prva svetovna vojna mu je v Tirolah prekrižala načrte, moral je na fronto. Kmalu po ustanovitvi ljubljanske univerze je bil imenovan za provizornega uslužbenca in bil 22. februarja 1921 dodeljen geološko-paleontolo-škemu inštitutu. Prof. M. Salopek je v njem spoznal sposobnega in vestnega delavca in že 6. junija 1924 je bil postavljen za laboranta. Na tem mestu je ostal kot aktivni delavec do 1. aprila 1956, odtlej naprej pa kot honorarni delavec vse do konca prejšnjega leta, ko mu je neozdravljiva bolezen načela še poslednje moči. Simnovčeve velike sposobnosti, njegova delavnost in njegova velika ljubezen do dela v službi geologije so mu naklonile, da je dal v svojem poklicu veliko več, kot je od njega terjala laborantska služba. Poleg običajnih del se je lotil še študija osnovne določevalne paleontološke literature in s profesorjevimi nasveti uredil paleontološko zbirko in še dve manjši zbirki za študentske vaje in jih nenehno spopolnjeval. S pomočjo literature se je lotil določevanja različnih fosilnih ostankov iz naših krajev, nabranih na geoloških ekskurzijah. Veliko zanimanje in izreden spomin sta mu pomagala, da je kmalu poznal vse okamenine v obsežni zbirki in vedel zanje tudi potrebno literaturo. To pa je bilo neprecenljive vrednosti za študente, ki jim je znal vselej svetovati in pomagati, kolikor je mogel. Med službovanjem je prepariral nešteto najrazličnejših okamenin od vsepovsod; svoje bogate izkušnje pa je rad posredoval vsem, ki so ga prosili za pomoč. V njegovi skrbi je bila skozi štiri desetletja tudi obsežna inštitutska knjižnica in vzorne kartoteke so njegovo delo. Poznal je domala vso domačo in tujo strokovno literaturo in ni ga bilo boljšega svetovalca študentom, kot je bil naš Simnovec. Številni geologi in drugi strokovnjaki so še po končanem študiju prihajali k njemu po literaturo in nasvete. S svojim tehničnim znanjem in natančnostjo je v inštitutu v celoti nadomestil še tehničnega risarja. Izdelal je več zahtevnih rokopisnih geoloških kart slovenskih specialk, mnoge geološke skice in številne študijske pripomočke za predavanja. Seveda so tudi sposobnosti njegovega prvotnega poklica prišle vsepovsod do veljave. Vselej in povsod se je zavzemal za ugled inštituta, najbolj pa je to dokazal s svojim vestnim in natančnim ter predanim delom slovenski geologiji. Skoraj vse generacije slovenskih geologov je spremljal od začetka študija do diplome, pomagal pa je še številnim študentom biologije, geografije, gradbeništva in rudarstva. In prav vsem je ostala globoka hvaležnost za njegovo nesebično pomoč, ki jo je delil na vse strani. Ob intimni slovesnosti njegovega 45-letnega laborantskega dela je bil otroško vesel, da ga imajo njegovi študentje tako radi in so se ga tako prisrčno spomnili. S svojim delom pa je zaslužil, da se ga s hvaležnostjo spominjamo tudi sedaj, ko ga ne bo več med nami. A. Ramovš GEOLOGIJA — Razprave in poročila — Geological Transactions and Reports I izdajajo: Geološki zavod v Ljubljani, Inštitut za geologijo univerze v Ljubljani in Slovensko geološko društvo — Published by Geological Survey Ljubljana, Institute of Geology, and Slovene Geological Society I Uredniški odbor — Editorial Committee: Boris BERCE, GeoLoSki zavod Ljubljana; Marjan DOLENC, Geološki zavod Ljubljana; Jože DUHOVNIK, Fakulteta za naravoslovje in tehnologijo univerze v Ljubljani; Danilo JELENC, Adctts Ababa; Stefan KOLENKO, Geološki zavod v Ljubljani; Dušan KUSCER, Inštitut za geologijo univerze v Ljubljani; Slavko PAPLER, Geološki zavod Ljubljana; Marlo PLENICAH, Geološki zavod Ljubljana t Glavni urednik — Editor in chief: Stefan KOLENKO, Ljubljana, Parmova cesta 33 ! Natisnila — Printed by Tiskarna Ljudske pravice Ljubljana